There is no reason to suppose she's lying.

认为她在说谎完全没道理。

《牛津词典》

It is ingenuous to suppose that money did not play a part in his decision.

如果以为他的决定没有金钱的因素，那就太天真了。

《牛津词典》

youdao

"If I felt that I could have been increasingly effective in that job, I suppose I would have continued to do it.

VOA: special.2010.05.09

And Moses admonishes the Israelites not to suppose that their inheritance of the land of Canaan is due to their own powers, or on account of any righteousness or virtue that they possess.

摩西警告以色列人不要想当然地认为,他们继承迦南之地是凭借了自己的力量，或者视之为他们所拥有的正义和美德。

耶鲁公开课 - 旧约导论课程节选

But I suppose it's better to have an idea of British people being posh

但是我想，大家认为英国人很高傲会更好一些，

优雅的英式英语 - SpeakingMax英语口语达人

There is no reason to suppose that this would not have the support of ordinary Afghans.

BBC: Who should take control of Kabul?

It is also fanciful to suppose that Kabul can be demilitarized without some faction trying to grab power.

CNN: A Workable Plan

Against that, there are reasons to suppose that the economy will hold up.

ECONOMIST: Singing in the rain