"Can bet on it" is a phrase that expresses confidence in something happening. However, there are several antonyms for this phrase that indicate uncertainty or doubt. Some of these antonyms include "unlikely," "doubtful," "uncertain," "questionable," and "unreliable." When someone says they "can't bet on it," they mean they do not have faith in the outcome. These antonyms can be useful in indicating when something may not be a sure thing or when one should approach a situation with caution. It is important to consider both sides of a situation before placing bets, both literally and figuratively.