unsure

形容词 unsure:

1. lacking or indicating lack of confidence or assurance
   同义词：uncertain, incertain
2. lacking self-confidence
   同义词：diffident, shy, timid

1. Beneath her self-confident surface, she's quite unsure of herself.
   她看上去信心十足，实际上很缺乏信心。
2. As if unsure of where she was, she hesitated and looked round.
   她彷佛茫然不知身在何处，犹犹豫豫向四周打量。

un.sure

adj.（形容词）
Lacking confidence.
缺乏自信的
Uncertain of the facts.
不确定事实的
Precarious; unstable; unreliable.
不稳定的，不固定的；不可信任的；不可靠的

【引伸】
unsure.ly
adv.（副词）