他们不相信婚姻。

They don't believe in marriage.

《牛津词典》

他们不相信这次调查的结果。

They could give no credence to the findings of the survey.

《牛津词典》

要是他们不相信他，他们会对他怎样？

Suppose they did not believe him, what would they do to him?

《新英汉大辞典》

But, you know, any professor who stands before you should say the same thing about his or her subject. If they don't believe that, they shouldn't be teaching.

但是，你知道，所有站在你们面前的老师,可能都会这样介绍他的课程,如果他们不那样相信着，那他们就不应该教那门课了。

麻省理工公开课 - 固态化学导论课程节选

Some people say they eat human flesh at these dinners, but you doubt that because for some reason they seem to be all vegetarians.

有人说他们吃人肉，但你不太相信,因为他们看着像是素食者。

耶鲁公开课 - 新约课程节选

And I think many parents believe that if they didn't persist in using these things their children would never learn to speak.

我相信很多父母认为,如果他们不坚持使用这些东西,他们的孩子将永远也学不会说话

耶鲁公开课 - 心理学导论课程节选