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

没有适当的回报，那些做了好事的人有时会觉得失望，而许多其他的人则干脆不愿做好事。

Without proper rewards, those who have done good deeds may sometimes feel disappointed and many others will simply shy away from doing good deeds.

youdao