In the first place, you shouldn't believe in promises. The world is full of them: the promises of riches, of eternal salvation, of infinite love. Some people think they can promise anything, others accept whatever seems to guarantee better days ahead, as, I suspect is your case. Those who make promises they don't keep end up powerless and frustrated, and exactly the fate awaits those who believe promises. 

Words can be twisted into any shape. Promises can be made to lull the heart and seduce the soul. In the final analysis, words mean nothing. They are labels we give things in an effort to wrap our puny little brains around their underlying natures, when ninety-nine percent of the time the totality of the reality is an entirely different beast. The wisest man is the silent one. Examine his actions. Judge him by them.