A lot of promises are made only to be broken at some point in life.
Sometimes, there's no choice but to break them. Whereas, sometimes, promises get broken because the initial condition was absurd or too hard to keep.
The key to being trustworthy and keeping promises is to promise only what you can live up to. Sure, there will be a time when you are sure that you can hold your end of the bargain while making your promise only to find out at a later point that you can't.
That's fine. You don't have to live up to every promise you've ever made.
The problem is when you become a serial deal breaker. That is when you lose your trustworthiness.
Don't be someone who's just talk and no action. Think before making a promise.
As for me, I always try to live up to what I promise. However, I have broken a few in the past where I had to choose between my life and someone else's.
I just had to.
This is the reason why now I think carefully before making any promise.
An honest upfront denial is better than a false promise.
Deny upfront or hold your end of the bargain. Be fair.