honest!

honest

An expression used to emphasize the veracity of one's statement. I swear it wasn't me who broke the lamp, honest!
Farlex Dictionary of Idioms.

honest!

(spoken) used to emphasize that you are not lying: I didn’t mean it, honest!
Farlex Partner Idioms Dictionary
See also:
  • out of one's
  • on one's
  • on someone's
  • (Have you) been OK?
  • monkey's uncle, I'll be/am a
  • at one's
  • at someone's
  • (I've) got to go
  • #dead
  • (Well) I'll be a monkey's uncle!