Cross my heart (and hope to die) kids spoken language informal verb phrase
Usually used by children, or by parents to children
Added to a statement or a promise to show that you are being honest in what you said.
It was George who left the door unlocked, cross my heart and hope to die!
A: "Did you cheat on the exam?" B: "No, I didn't. Cross my heart."
Used to say that you'll do what you promise
I won't tell anyone your secrets. I promise, cross my heart.
To do what you promised to do or what people expect you to do
Promises do not guarantee that something will happen.
The verb "cross" should be conjugated to its tense.
The phrase most likely originated based upon the familiar Catholic sign of the cross. It is commonly accompanied by hand gestures such as crossing one's hands over one's breast and then pointing the right hand skyward. Today most often used by children. It is first recorded in Fashions and Follies of Washington Life, a play by Henry Clay Preuss:
"– Capt. S. Attended strictly to everything I told you?
– Tom. Yes indeed, Massy—cross my heart!"