1、guarantee

例句：Unity is the guarantee of victory.

团结是胜利的保证。

2、insure

例句：To insure the highest volume of milk, the calf is taken away from her immediately after birth.

为了确保生产最大量的牛奶，小牛犊一出生就被立刻从母奶牛身边带走。

3、make certain

例句：Make certain you value and allow rest and recovery time.

确信你重视并允许休息和恢复时间。

4、Ensure

例句：But how can you ensure that.

但是如何才能确保这点呢。

5、assure

例句：Jack assured himself that they did as they were told.

杰克确信他们是按照要求的那样去干的。