What is a promise? When you make a promise, you are giving your word that you will do the thing promised in a timely manner. Problems can arise when you do not keep your promise and the relationship between the two people can break down.
“Be impeccable with your word” is one of the Four Agreements in the book by Don Miguel Ruiz (it’s one of my favorites!) Do you keep your promises? Can people count on you to do what you promise to do, when you say you will do it? In order to build a successful relationship, there has to be credibility and truthfulness in your words. People need to know they can count on you. One of the quickest ways to show this is by keeping your promises. The reverse is also true — one of the quickest ways to destroy a relationship is to not keep your promises.
Have you ever had someone ask you to make a promise and you said “yes” and almost immediately you wished your answer had been “no”? Best to go ahead and keep the promise, learn your lesson and be more careful and think about it a little longer next time. But always let your “yes” truly be a yes and your no be a definite no.