The term "be in a quandary" generally refers to being perplexed or uncertain about something. To express the opposite meaning, we can use a variety of antonyms, such as confident, decisive, certain, resolute, or clear-minded. Someone who is confident is assured and sure of their decision or action, while a person who is clear-minded has a clear understanding of the situation at hand. Being decisive means that you can quickly and efficiently make a decision, while being resolute connotes a person who is firm and unwavering in their beliefs or decisions. Using these antonyms, we can communicate the complete opposite of being in a quandary.