没有什么可以保证每个人都愿意付出努力；学生的辛苦学习是否能得到适当的回报，这是没有把握的。

There is nothing to guarantee that everybody is willing to make the effort; there is no assurance that the learner will have any adequate return for his toil.

youdao

在没有把握的时候，你要等待。

In times of uncertainty, wait.

youdao

他们用更多的努力认清自己，很多时候，他们最没有把握的方面恰恰也是他们最杰出的地方。

They worked harder to confirm for themselves that they really did belong. Often the most insecure of them were also the most brilliant.

youdao

Then again, if you are not certain of something you can say "I'm not sure."

同样的，如果你对于一件事没有把握，你可以说“I'm not sure.”

I'm sure 课堂 - SpeakingMax英语口语达人