Antonyms of the phrase "placed confidence in" could include words like distrust, doubt, suspicion, skepticism, uncertainty, and disbelief. When we place our confidence in someone or something, we believe in their abilities, trust their judgment, and have faith in their reliability. Conversely, when we don't have confidence in someone or something, we doubt their capabilities, question their motives, and may even fear being let down or hurt. While it's important to have faith in others, it's equally important to exercise caution and skepticism when necessary, and to maintain a healthy level of doubt until trust has been earned.