put/set (someone's) mind at rest

to make someone stop worrying.

If it'll put your mind at rest, I can drive you home and you can make sure the door's locked.

• feed someone a line
• feed someone to the lions
• not have a bone in your body
• not have a care in the world
• not have a cat in hell's chance
• not have a chance in hell
• not have a clue
• not have a dog's chance
• not have a hope in hell
• not have a leg to stand on
• not have a minute to call own
• not have a minute to call your own
• not have a monopoly on
• not have a monopoly on something
• not have a pot to piss in
• not have a prayer
• not have a snowball's chance in hell
• not have a type of bone in body
• not have a type of bone in your body
• not have much going for
• not have much going for you
• not have much time
• not have much time someone
• not have much time something
• not have the faintest