He used a phrase I hate: "You have to be cruel to be kind."

他用了一句我讨厌的习语：“要想善良，就得残忍。”

《柯林斯英汉双解大词典》

The little boy's mother taught him to be kind and friendly.

这个小男孩的母亲教他要善良和友好。

youdao

After a few minutes, she told them to be kind to their new classmate, and then she left.

几分钟后，她告诉他们要善待他们的新同学，然后她离开了。

youdao

Yet,the people in those areas never forgot how to be kind and friendly to strangers.

VOA: special.2010.05.08

But how is it then to meet someone at a different religion and different political persuasion, and yet still be able to be kind to one another.

那你们遇见来自不同宗教,不同政治倾向性的人是什么感受，而且你们仍然可以彼此成为朋友。

普林斯顿公开课 - 人性课程节选

you know, people dressed in gold and things like that, pretending to be kind of statues

人们穿上金色的服装和类似的东西，假装是一尊雕像，

伦敦的约会路线 - SpeakingMax英语口语达人

Jobs and Gates's lessons to managers aren't about being cruel to be kind or successful.

WSJ: Successful CEOs Don't Have to Be Jerks

Instinctively, we want to be kind to each other, especially out on the road.

BBC: Viewpoint: Is it time to get rid of traffic lights?

To be kind, this org is effectively advocating censorship under the banner of transparency.

FORBES: Why Employers Should Stop Worrying About Health Costs