what (someone) doesn't know won't hurt them

what (someone) doesn't know won't hurt them

Remaining ignorant or uninformed about something will allow someone to not have to worry about, feel responsible for, or get upset by it. A: "Where are you going?" B: "It's better that you stay in the dark about this. What you don't know won't hurt you." A: "Mom will freak out if she finds out that you took the car without asking!" B: "Of course she will. But what Mom doesn't know won't hurt her."

See also: hurt, know, what

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

what one doesn't know won't hurt one

Cliché Unknown facts cannot worry or upset a person. Don't tell me that I have made a mistake. What I don't know won't hurt me. Don't tell him the truth about his missing dog. What he doesn't know won't hurt him.

See also: hurt, know, one, what

What you don't know won't hurt you.

 and What you don't know can't hurt you.

Prov. If you do not know about a problem or a misdeed, you will not be able to make yourself unhappy by worrying about it. (Often used to justify not telling someone about a problem or misdeed.) Ellen: What a beautiful diamond necklace! Thank you! But how on earth did you get the money to pay for it? Fred: What you don't know won't hurt you.

See also: hurt, know, what

McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.