Antonyms are words with opposite meanings, and for "was confident of", antonyms may include feelings of doubt, uncertainty, insecurity, and hesitation. Some antonyms for "was confident of" may include phrases such as "was unsure of", "was doubtful about", "had no faith in", "lacked confidence in", "was hesitant about", or "was uncertain of". These antonyms can be used in different contexts and situations to convey the opposite feeling of confidence. Using antonyms in writing or speech can add nuance and depth to communication by presenting contrasting or alternative ideas.