我郑重承诺我会回来的。

I made a solemn promise that I would return.

《牛津词典》

我会不得不承诺我无法实现的诺言；兜售一些东西给那些正在寻找答案的人们，而这些答案我也没有；欺骗他们让他们来买这本书。

I'd have to make promises I couldn't deliver on, sell something to people who are looking for answers I don't have, trick them into buying the book.

youdao

我选择了后者，接受挑战，就在那个晚上，我对那11个孩子承诺，我会把我们的乐团变成世界顶级乐团。

I decided to face the challenge, and on that same night, I promised those 11 children I'd turn our orchestra into one of the leading orchestras in the world.

youdao

The goldsmith in your town writes out a note saying, I will pay to the bearer of this note so much gold, and then the bearer could be anyone.

你居住城镇的金匠写下票据并承诺,我会付给持票人这么多数量的金子,任何人都可以是持票人

耶鲁公开课 - 金融市场课程节选