B2 · 中上級 チャプター 15

Expressing Certainty and Logic

5 トータルルール
51 例文
5 分
このチャプターのルール クイック練習

Chapter in 30 Seconds

Master the art of logical deduction and unwavering certainty in natural Korean conversation.

  • Express logical probability based on external circumstances.
  • Deny possibilities and confirm absolute facts with authority.
  • Make educated guesses about the past and concede points gracefully.
Speak with conviction, reason with logic.

学べること

In this chapter, you're about to take a big leap and speak like a true Korean native! You'll move beyond just saying "I'm sure or I think"; you'll learn to precisely and subtly convey your level of certainty and logic in your speech. Imagine your friend hasn't arrived yet, and you see heavy traffic; by learning «-ㄹ/을 법하다,» you can say, "They're likely stuck in traffic." Or, when you're 100% sure something is impossible, with «-ㄹ 리가 없다,» you can decisively say, "There's no way!" In this lesson, you'll learn powerful tools like «-ㄹ/을 게 분명하다» to express yourself without a shred of doubt when you're absolutely certain about something. Wow, how great it is not to worry anymore! You can even use «-았/었을 것이다» to logically deduce about past events you didn't personally witness, like

They must have gone out yesterday.
These structures fit together like a puzzle, allowing you to express anything from a likely guess to absolute certainty in the best possible way. After this chapter, you'll be able to confidently express your opinions with reasoning and certainty in any conversation. You'll even learn how to use «-기는 하다» to concede a point politely before adding a small but and qualifying your statement. Ready for a much deeper and more authentic Korean conversation? Let's get started!

Learning Objectives

By the end of this chapter, you will be able to:

  1. 1
    By the end you will be able to describe likely scenarios using -ㄹ/을 법하다 based on logical reasoning.
  2. 2
    By the end you will be able to strongly negate impossible situations using -ㄹ 리가 없다.
  3. 3
    By the end you will be able to reconstruct past events logically using -았/었을 것이다.

チャプターガイド

Overview

Welcome, B2 Korean learners! Are you ready to elevate your Korean grammar to a truly native-like level? This chapter is your gateway to expressing certainty and logic with precision and nuance.
Moving beyond simple I think or "I'm sure," you'll master expressions that allow you to convey exactly how confident you are about a statement, or how logically you've deduced something. This is a crucial step in achieving fluency and engaging in deeper, more authentic conversations.
At the B2 CEFR level, the expectation is to communicate effectively in a wide range of situations, and that includes expressing your thoughts with conviction and sound reasoning. By learning structures like -ㄹ/을 법하다 for likelihood, -ㄹ 리가 없다 for impossibility, -ㄹ/을 게 분명하다 for absolute certainty, and -았/었을 것이다 for logical past deductions, you'll gain the tools to articulate your opinions with confidence. You'll even learn -기는 하다 to gracefully concede a point before introducing a counter-argument.
These advanced Korean grammar patterns will make your speech more sophisticated and natural, helping you sound less like a textbook and more like a native speaker.

How This Grammar Works

Let's dive into the powerful tools for expressing certainty and logic in Korean. First, for expressing that something is logically likely or probable, we use -ㄹ/을 법하다. This structure suggests that based on circumstances, something seems like it could reasonably happen.
For instance, «그는 바빠서 못 올 법해요» (He's busy, so he's likely unable to come). When you're absolutely certain that there's no way something could be true, you'll use -ㄹ 리가 없다. It conveys strong disbelief or a logical impossibility.
For example, «그가 거짓말을 했을 리가 없어요» (There's no way he lied).
To express absolute certainty, when you have no doubt whatsoever, the phrase -ㄹ/을 게 분명하다 is your go-to. It means "it's clear that or it must be. Imagine saying, 내일 비가 올 게 분명해요" (It's definitely going to rain tomorrow). For making a logical past guess, like deducing what must have happened, we use -았/었을 것이다.
This is perfect for speculating about past events you didn't witness but can logically infer. For example, «그는 어제 집에 일찍 갔을 거예요» (He must have gone home early yesterday). Finally, to acknowledge with a 'but', or to concede a point before offering a qualification, we use -기는 하다.
This softens your statement and adds nuance. For instance, «맛있기는 한데, 너무 비싸요» (It is delicious, but it's too expensive). Mastering these B2 Korean grammar structures will significantly enhance your expressive capabilities.

Common Mistakes

  1. 1✗ Wrong: «비 올 것 같아.» (Sounds too casual/simple for strong certainty)
✓ Correct: «비가 올 게 분명해요.» (It's definitely going to rain.)
*Explanation:* While «것 같다» expresses probability, -ㄹ/을 게 분명하다 conveys a much stronger, almost undeniable certainty, which is what the speaker truly intends here.
  1. 1✗ Wrong: «그가 어제 집에 일찍 가야 했어.» (This implies 'had to go,' not 'must have gone' as a deduction)
✓ Correct: «그는 어제 집에 일찍 갔을 거예요.» (He must have gone home early yesterday.)
*Explanation:* -았/었을 것이다 is specifically for logical deduction about past events. «가야 했어» means he *had* to go, indicating obligation, not inference.
  1. 1✗ Wrong: «이 음식은 맛있어. 하지만 비싸.» (A bit blunt, lacks nuance)
✓ Correct: «이 음식은 맛있기는 한데, 너무 비싸요.» (This food is delicious, but it's too expensive.)
*Explanation:* -기는 하다 acknowledges the positive aspect (delicious) first, then gently introduces the negative (expensive), making the statement more polite and nuanced than a direct but.

Real Conversations

A

A

지영 씨가 아직 안 왔네요. (Jiyoung hasn't arrived yet.)
B

B

길이 많이 막히는 걸 보니, 늦을 법해요. (Seeing the heavy traffic, she's likely going to be late.)
A

A

그 어려운 시험에 그가 합격했을까요? (Do you think he passed that difficult exam?)
B

B

그가 밤새 공부한 걸 보면, 합격했을 리가 없어요. (Considering he studied all night, there's no way he didn't pass. / He must have passed.)
A

A

이 프로젝트는 내일까지 끝낼 수 있을까요? (Can we finish this project by tomorrow?)
B

B

팀원들이 열심히 하고 있으니, 분명히 끝낼 수 있을 게 분명해요. (Since the team members are working hard, it's clear we'll be able to finish it.)

Quick FAQ

Q

What's the main difference between -ㄹ/을 법하다 and just using 아마 (probably)?

While 아마 expresses general probability, -ㄹ/을 법하다 specifically implies that something is *logically reasonable* or *plausible* given the circumstances, often based on common sense or observable facts. It adds a layer of reasoned deduction.

Q

Can -았/었을 것이다 be used for future deductions?

No, -았/었을 것이다 is exclusively for logical deductions about *past* events. For future deductions, you would typically use -ㄹ/을 것이다 (e.g., «내일 비가 올 것이다» - It will probably rain tomorrow).

Q

Is -ㄹ 리가 없다 considered informal?

No, -ㄹ 리가 없다 is a versatile expression usable in both formal and informal contexts. Its formality depends more on the politeness level of the ending (e.g., -ㄹ 리가 없어요 vs. -ㄹ 리가 없어).

Q

When is -기는 하다 more appropriate than a simple yes, but...?

-기는 하다 is perfect when you want to acknowledge a point or agree with something, but immediately want to add a caveat, a criticism, or a different perspective. It softens the but and shows you've considered the other side.

Cultural Context

These expressions of certainty and logic are deeply embedded in how native Korean speakers communicate, reflecting a culture that values thoughtful consideration and polite nuance. Using structures like -ㄹ/을 법하다 allows for logical reasoning without sounding overly assertive, while -기는 하다 enables polite disagreement or qualification, crucial in a high-context society. You'll hear these B2 Korean grammar patterns frequently in everyday conversations, news analysis, and even debates, as they allow speakers to express strong opinions with appropriate levels of confidence and deference.
Mastering them will not only improve your grammar but also your cultural understanding.

重要な例文 (8)

1

이 시간쯤이면 차가 막힐 법해요.

この時間なら、道が混んでいるのが当然です。

論理的な推測: -(으)ㄹ 법하다
2

그 식당은 리뷰가 많아서 맛있을 법해.

あの店はレビューが多いから、きっと美味しいはずだよ。

論理的な推測: -(으)ㄹ 법하다
3

James-ga geu don-eul humchyeoss-eul li-ga eops-eoyo.

ジェームズがそのお金を盗んだはずがありません。

〜するはずがない (-ㄹ 리가 없다)
4

Beolsseo maejin-il li-ga eopseo! Il-bun-bakk-e an jinatneunde.

もう売り切れなわけないよ！1分しか経ってないのに。

〜するはずがない (-ㄹ 리가 없다)
5

그 영화는 재미있을 게 분명해요.

その映画は面白いに違いありません。

絶対的な確信を表す (-ㄹ/을 게 분명하다)
6

그는 벌써 잤을 게 분명해요.

彼はもう寝たに違いありません。

絶対的な確信を表す (-ㄹ/을 게 분명하다)
7

어제 비가 많이 `왔을 거예요`. 땅이 다 젖어 있거든요.

昨日は雨がたくさん降ったはずです。地面がすっかり濡れていますから。

論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)
8

민수 씨는 벌써 `퇴근했을 거예요`. 사무실 불이 꺼져 있어요.

ミンスさんはもう退勤したはずです。オフィスの電気が消えています。

論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)

ヒントとコツ (4)

💡

「当たり前」のニュアンス

結果が誰の目にも明らかな時に使います。「一晩中勉強したんだから、合格して当然だ」というような、自然な流れを表現します。«열심히 했으니 이길 법해.»
frontend.learn_grammar.from_rule: 論理的な推測: -(으)ㄹ 법하다
💬

ドラマの定番セリフ

韓国ドラマの衝撃的なシーンでよく耳にする表現です。感情を込めて叫んでみましょう: «말도 안 돼! 그럴 리가 없어!» (ありえない！そんなはずない！)
frontend.learn_grammar.from_rule: 〜するはずがない (-ㄹ 리가 없다)
🎯

「게」が自然さの鍵！

「게」は「것이」が会話で崩れた形です。これを使うだけで、一気にネイティブっぽいこなれた雰囲気になりますよ。 «맛있을 게 분명해요.»
frontend.learn_grammar.from_rule: 絶対的な確信を表す (-ㄹ/을 게 분명하다)
🎯

「根拠」があるかチェック！

この表現は、何らかのヒントがある時に使います。根拠がなく、ただ「〜だったかも？」とあいまいに言うなら «-았/었을지도 몰라요» を選ぶのが正解です。 «땅이 젖어 있는 걸 보니 비가 왔을 거예요.»
frontend.learn_grammar.from_rule: 論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)

重要な語彙 (6)

분명하다 to be clear/certain 이유 reason 교통 체증 traffic jam 인정하다 to admit/acknowledge 가능성 possibility 확실히 certainly/definitely

Real-World Preview

clock

The Late Friend

Review Summary

  • V/A + -ㄹ/을 법하다
  • V/A + -ㄹ/을 리가 없다
  • V/A + -았/었을 것이다

よくある間違い

The pattern is almost exclusively used with '없다' to show impossibility. Using '있다' makes it a rhetorical question which is much rarer.

Wrong: 그가 올 리가 있어요? (Is there a way he's coming?)
正解: 그가 올 리가 없어요. (There's no way he's coming.)

In spoken Korean, -ㄹ 것이에요 is almost always contracted to -ㄹ 거예요. Using the uncontracted form sounds overly stiff.

Wrong: 어제 갔을 것이에요.
正解: 어제 갔을 거예요.

-기는 하다 feels incomplete without a contrasting clause (하지만/한데). It is used to concede a point before adding a 'but'.

Wrong: 그는 똑똑하기는 해요. (He is smart.)
正解: 그는 똑똑하기는 하지만 공부는 안 해요. (He is smart, but he doesn't study.)

このチャプターのルール (5)

1

論理的な推測: -(으)ㄹ 법하다

B2
根拠がある論理的な推測をしたい時に使いましょう。「«논리적 추측»」「«당연한 결과»」「«객관적 근거»」がこの文法のキーワードです。
이 시간쯤이면 차가 막힐 법해요.
10 例文
2

〜するはずがない (-ㄹ 리가 없다)

B2
自分の論理や常識に照らし合わせて「100%ありえない！」と確信した時に使う魔法のフレーズです。«ㄹ/을 리가 없다» を使って、あなたの意思をはっきり伝えましょう。
James-ga geu don-eul humchyeoss-eul li-ga eops-eoy...
10 例文
3

絶対的な確信を表す (-ㄹ/을 게 분명하다)

B2
「間違いない！」と確信した時は «-ㄹ/을 게 분명하다» を使いましょう。根拠がある時の «強い自信» が伝わりますよ。
그 영화는 재미있을 게 분명해요.
10 例文
4

論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)

B2
自分の目で見ていない過去の出来事について、根拠を持って「〜したはずだ」「〜だっただろう」と推論する時は «-았/었을 것이다» を使いましょう。
어제 비가 많이 `왔을 거예요`. 땅이 다 젖어 있거든...
10 例文
5

「〜ではあるけれど」の認め (-기는 하다)

B2
相手の意見を「認める」時に使い、その後に「でも」と「条件」を付け加えることができますよ。
그 영화가 재미있기는 한데 너무 길어요.
11 例文

Next Steps

You've just added a layer of sophistication to your Korean that many learners never reach. You are now capable of debating and reasoning like a true B2 speaker!

Watch a Korean mystery drama and narrate your theories using -ㄹ 게 분명해요.

Write 5 sentences about your childhood using -았/었을 것이다 for things you don't remember clearly.

Continue to: Inevitability and Close Calls

クイック練習 (10)

確信を表す形に直して空欄を埋めてください。

내일은 날씨가 ___ 분명해요. (좋다)

✓ Correct! ✗ Not quite. Correct answer: 좋을 게
形容詞「좋다」にはパッチムがあるので、-을 게 を付けます。

frontend.learn_grammar.from_rule: 絶対的な確信を表す (-ㄹ/을 게 분명하다)

「ありそうな話です」という文章を完成させてください。

그것은 그럴 ___ 이야기예요.

✓ Correct! ✗ Not quite. Correct answer: 법한
그럴 법하다（ありそうだ/妥当だ）を連体形にして名詞を修飾します。

frontend.learn_grammar.from_rule: 論理的な推測: -(으)ㄹ 법하다

譲歩のパターンを正しく使っている文章を選んでください。

Choose the most natural sentence for 'It is cheap, but not good':

✓ Correct! ✗ Not quite. Correct answer: 싸기는 한데 좋지 않아요.
形容詞の語幹「싸-」に「-기는」をつけ、「한데」で二つの考えをつなぐのが正しい方法です。

frontend.learn_grammar.from_rule: 「〜ではあるけれど」の認め (-기는 하다)

分かち書きを直してください。

Find and fix the mistake:

그는성공할법하다.

✓ Correct! ✗ Not quite. Correct answer: 그는 성공할 법하다.
連体形の「성공할」と「법하다」の間を空けるのが標準的な書き方です。

frontend.learn_grammar.from_rule: 論理的な推測: -(으)ㄹ 법하다

強い確信を表すのに最も自然な文を選んでください。

レストランの行列を見て「絶対においしいはずだ」と言いたい時：

✓ Correct! ✗ Not quite. Correct answer: 이 식당은 맛있을 게 분명해요.
-ㄹ 게 분명해요 は -ㄹ 것 같다 よりもずっと強い確信を表します。

frontend.learn_grammar.from_rule: 絶対的な確信を表す (-ㄹ/을 게 분명하다)

短縮形の間違いを見つけて修正してください。

Find and fix the mistake:

한국어가 어렵긴은 하지만 재미있어요.

✓ Correct! ✗ Not quite. Correct answer: Both are correct.
「-긴」は「-기는」の短縮形ですが、「긴은」のように両方を一緒に使うことはできません。完全に「-기는」を使うか、短縮形の「-긴」を使うかのどちらかです。

frontend.learn_grammar.from_rule: 「〜ではあるけれど」の認め (-기는 하다)

「知っている(알다)」を使って文章を完成させてください。

彼は昨日着いたばかりだよ。秘密のパスワードを ___ ___ ___ ___ ! (知っているはずがない)

✓ Correct! ✗ Not quite. Correct answer: 알 리가 없어
「知っている道理がない」という意味にするために、語幹 알 に 리가 없어 を繋げます。

frontend.learn_grammar.from_rule: 〜するはずがない (-ㄹ 리가 없다)

「好きは好きなんだけど…」と表現するように、空欄を埋めてください。

피자를 좋아___ 한데 너무 비싸요.

✓ Correct! ✗ Not quite. Correct answer: 기는
何かを好きであることを認めつつ、何か言いたいことがある場合に「-기는」の形を使います。

frontend.learn_grammar.from_rule: 「〜ではあるけれど」の認め (-기는 하다)

「暑かったはずです」という意味として正しい文を選んでください。

正しい文を選んでください：

✓ Correct! ✗ Not quite. Correct answer: 더웠을 거예요.
形容詞「덥다 (暑い)」の過去推測形は「더웠을 거예요」になります。

frontend.learn_grammar.from_rule: 論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)

次の文の間違いを直してください： '그는 어제 밥을 먹을 거예요.'

Find and fix the mistake:

그는 어제 밥을 먹을 거예요.

✓ Correct! ✗ Not quite. Correct answer: 그는 어제 밥을 먹었을 거예요.
「어제 (昨日)」という過去の単語があるため、推測の語尾の前に過去の時制を表す「-었-」を入れる必要があります。

frontend.learn_grammar.from_rule: 論理的な過去の推測： 「〜したに違いない」 (-았/었을 것이다)

Score: /10

よくある質問 (6)

はい！ -었/았을 법하다 という形を使います。「（今の証拠から見て）〜した可能性が高い」という意味になります。«그때는 그럴 법했어.»
그럴 법하다 は論理的な妥当性に重点を置きます。一方、그럴 듯하다 は「もっともらしい（けど本当かはわからない）」というニュアンスが含まれることがあります。«그럴듯한 핑계»
漢字の「理（ことわり）」から来ています。「論理」や「理由」という意味なので、直訳すると「論理が存在しない」となります。例えば «그럴 리가 없다» は「そうなる道理がない」という意味です。
はい！使えますよ。例えば、自分がやった覚えがない時に «내가 그럴 리가 없어» (私がそんなことするはずない) と言えます。
-ㄹ 것이다 は一般的な未来や単純な推測ですが、-ㄹ 게 분명하다 は証拠に基づいた「強い確信」を加えます。 «갈 거예요»（行きます/行くでしょう）と «갈 게 분명해요»（行くに違いありません）の違いですね。
はい！ -았/었을 게 분명하다 を使います。例えば «그는 이미 밥을 먹었을 게 분명해요»（彼はもうご飯を食べたに違いありません）のように言えます。
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