bet your bottom dollar/your life

bet your bottom dollar

Be certain that something will happen (so much so that one would hypothetically risk one's last dollar betting on it). I lost my umbrella, so you can bet your bottom dollar that it will rain tomorrow! Oh, you can bet your bottom dollar that Kevin will be late tonight—he's never on time!

See also: bet, bottom, dollar

(you can) bet your bottom ˈdollar/your ˈlife (on something/that...)

(informal) (you can) be certain of something: You can bet your bottom dollar that he’ll forget our anniversary.

See also: bet, bottom, dollar, life