Being in a quandary, meaning to be uncertain or indecisive, can have its opposite in several different antonyms, each representing a distinct state of mind. One such antonym is 'resolute,' which implies determination and a clear sense of purpose. Another antonym could be 'decisive,' which denotes a confident and definitive choice. 'Assured' could also be considered an antonym, suggesting a sense of certainty and confidence in one's decisions. Similarly, 'resolved' or 'unambiguous' also contradicts being in a quandary, indicating a clear and definitive understanding or solution. Ultimately, the choice of antonym depends on the specific context and desired tone, but any of these options would provide a suitable contrast to being in a quandary.