安心する

Can be used with the particle 「に」 to express relief about a specific situation or person. For example, 「彼に安心した」 (I was relieved about him).

新しい先生がとても優しくて、子供たちはすぐに**安心した**。 (The new teacher was very kind, and the children quickly **felt at ease**.)

Often appears in the form 「安心しました」 to express that one has been relieved. This is a polite past tense form.

手術が無事に終わって、本当に**安心しました**。 (I was truly **relieved** that the surgery finished safely.)

Can be used with 「て」 form verbs to mean 'feel relieved after doing something'. For example, 「確認して安心する」 (feel relieved after confirming).

荷物が届いたと聞いて、**安心した**。 (I **felt relieved** to hear that the package had arrived.)

Can be followed by 「させる」 to make someone else feel relieved. For example, 「親を安心させる」 (make one's parents feel relieved).

君が無事で**安心させて**くれた。 (You **made me feel relieved** by being safe.)

Can be used in the negative form 「安心しない」 to mean 'not feel relieved' or 'not be at ease'.

テストの結果が出るまで、**安心できない**。 (I **can't feel at ease** until the test results come out.)