Definition of want to bet? in US English:

want to bet?

phrase

informal
  • Used to express vigorous disagreement with a confident assertion.

    ‘“You can't be with me every moment.” “Want to bet?”’
    • ‘“No-o-o-o - not me“, he replied. I asked him, “Do you wanna bet?”’
    • ‘Michael surprisingly then turned on his heal and added quickly, ‘want to bet?’’
    • ‘Dan said he didn't think it could be done effectively and Sean replied "Wanna Bet".’
    • ‘Estrella turned around, and looked him in the face with a challenging expression, as if to say, ‘Do you want to bet?’’
    • ‘When the pastor challenged the man with the notion that evolution might one day be laughed at by his grandchildren, he response was simply to retort angrily ‘do you want to bet?’’