bet one's bottom dollar

(US, slang, sometimes considered, _, vulgar) To bet everything; to have total reliance or confidence in something.

A British idiomatic expression meaning something is highly likely or virtually certain — equivalent to 'I'd bet anything.' The phrase draws on the imagery of offering heavily lopsided betting odds: if you stake a pound against someone else's penny, you're supremely confident in your position. Used to assert strong certainty, typically in a conversational or informal register. More common in older British speech; younger speakers might use 'I'd bet my life on it' or similar.

A British idiom expressing high confidence that something is true or likely to happen, essentially saying you would bet a pound against just a penny, meaning the odds are overwhelmingly in favor. Used to emphasize certainty about a prediction or claim. More colorful than simply saying almost certainly but functionally equivalent. The asymmetric financial metaphor makes the confidence tangible and specific.