The boring secret to perseverance is holding on despite the odds, hardship, and emotional roller coaster. And the foundation of someone holding on is faith. Now faith has nothing to do with science, as you might expect. But it's more scientific than you think. When you hold on and persevere, you increase your odds. With more time, new variables enter into the equation and if you are observant, you can simply walk on through when before there was a closed door. So if you think there is no hope, have faith. Do whatever you need to do except give up. That's what happened to me earlier today. Right now I can see the positive results of my having faith despite my doubts, doing what I could, and hanging on and letting time do its magic.
Keeping promises is hard. It requires us to do things we don't want to do. But keep those promises you must do. Otherwise, do not make them in the first place. But since you have made them, you must keep them, especially if it would benefit all those involved including yourself.