无自信的

例句：

1. 1. He always feels unconfident when speaking in public.
   他在公众场合讲话时总是感到不自信。
2. 2. She was unconfident about her ability to succeed in the competition.
   她对自己在比赛中取得成功的能力感到不自信。
3. 3. The young artist lacked confidence in his abilities and struggled to perform.
   这位年轻艺术家对自己的能力缺乏信心，表现不佳。