you bet your bottom

you bet your bottom

You can be sure that something will happen. A less vulgar alternative to "you bet your ass." You bet your bottom I'll be there tomorrow! A: "Hey, Frank, do you want to come with us to the movies?" B: "You bet your bottom I do!"
See also: bet, bottom
References in classic literature ?
and you bet your bottom dollar, Johnny, it AIN'T just as easy as it is for a cat to have twins
Would you bet your bottom dollar everyone will come out smelling of roses?