她的失败在某种程度上是由于缺乏信心。

His failure is in some measure due to lack of confidence.

youdao

事情做不好往往不是因为没能力，大都是由于缺乏信心。

Things are not well done due to lack of perseverance instead of inability.

youdao

同时，由于缺乏信心和安全感，她常常低估了自己的潜力。

Also, she often underestimates her potential due to her lack of confidence and a sense of security.

youdao