set (one's) mind at rest(redirected from setting their mind at rest)
set (one's) mind at rest
To assuage or relieve one's worry, anxiety, dread, fear, etc. I know you're anxious to hear how your father is doing after the surgery, so let me set your mind at rest: he's going to make a full recovery. That bonus really set my mind at rest about these debts.
set one's mind at rest
Also, put one's mind at rest. Stop worrying, allay one's anxiety. For example, Your car's been found undamaged, so set your mind at rest. Also see lay at rest.