If you make a promise, you should keep it.

如果你许下一个诺言，你就应该遵守它。

《柯林斯英汉双解大词典》

If you make a promise you should keep it!

如果做出承诺你就该去遵守！

youdao

You are my good friend, so you should keep it dark.

你是我的好朋友，所以你应该为我保守秘密。

youdao

"I think that growing up Asian, and as a woman, you're totally raised with this notion that you should keep it all inside and not have a lot of self-expression, " she said.

CNN: Losing weight, saying 'yes' in 2009

As one African delegate explained it to me: "if you make a legally-binding promise, you should keep to it".

BBC: Canada wins few friends on climate

Should you sell it or keep it?

FORBES: Sell Or Hold (Given Year-End Tax Rates)?