cheat on: 不忠于
Why do men cheat on their wives?
男人们为什么要欺骗他们的妻子呢？

deep down: 实际上，在心底
Deep down I knew I wasn't abandoned.
我的内心深处告诉我并没有被抛弃.
I think she must have wanted this, deep down.
我想在内心深处她一定希望看到这一切。

for no reason: 没有理由
Banks can become unsafe for no reason other than that everyone believes them to be unsafe.
银行不会无缘无故地变得不安全，除非所有人都认为它不安全。

believe in: 相信
I believe in the strength of community.
我相信社区的力量。
We are doing what we believe in.
我们在做自己信仰的事。