Students can confidentially report any problems they see in their schools.学生在学校里发现任何问题，都可以秘密举报。

He leaned forward confidentially and began telling his story.他神秘兮兮地俯身向前，开始讲述他的经历。

Confidentially, I don't think she's very good at her job.私下里说，我认为她不太胜任自己的工作。