You bet your sweet life!

you (can) bet your (sweet) life

You can be absolutely certain that something will happen. Sometimes used ironically. You bet your sweet life I'm going to that concert—I've been saving up for my ticket for months now! Oh, you can bet your life that Kevin will be late tonight—he's never on time! I lost my umbrella, so you can bet your life that it's going to rain soon.
See also: bet, life
Farlex Dictionary of Idioms.

You bet your sweet life!

exclam. You are absolutely correct! You bet your sweet life I am glad!
See also: bet, sweet
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • bippy
  • patootie
  • patoot
  • more like
  • more like (something)
  • none the worse (for something)
  • none the worse for
  • none the worse for something
  • seen worse
  • I've seen worse