Just because it is a kind of morals power, so it not is a law norm, having no the law binding force, also lack to fail in promise namely of make the roughly mechanism.

正是由于它是一种道德力量，所以它就不是法律规范，没有法律约束力，也即缺乏失信的制约机制。

youdao

I believe in you. But in the end, why do you still fail to keep your promise.

我相信你，可是为什么最后你依然没有做到你允诺的誓言。

youdao

Eg; 1 I promise my mother success in the exam. I can't fail it.

我向妈妈承诺过考试要成功，我不能失败。

youdao

After all, most mergers in most industries fail to live up to their promise.

ECONOMIST: Mining

Who among the downtrodden and the dispossessed can fail to be stirred by the promise of a world in which all men are equal, and each has what he needs?

FORBES: Magazine Article