放心 (fàng xīn): ผ่อนคลาย, รู้สึกสบายใจ

Don't worry, I will arrive on time.

The child arrived home safely, and only then did the mother feel relieved.

He doesn't feel very confident about this exam.

You can hand the task over to him and rest assured.

After hearing the doctor's explanation, I felt much more at ease.