我不能肯定事实是否如此。

I'm unsure of the facts.

youdao

我希望你能肯定你说的都是事实。

I hope you are sure of your facts.

《牛津词典》

经济增长肯定会使环境改善也绝非事实。

It's simply not true that economic growth will surely make our world cleaner.

youdao

Often,we just don't know how it got it, and it just happened because somebody just said, "It's authoritative. It must've been written by an apostle."

我们通常都不知道它是如何来的，它已经成了事实，因为有人说，“它具有权威，肯定是由一位使徒所写“

耶鲁公开课 - 新约课程节选