It also depends on whether or not they try to deliver on their promise as best as possible. Life can throw anything at us and it’s unreasonable to expect someone to deliver on a promise regardless of circumstances. If they never tried to fulfill their promise then it was a lie from the start and I wouldn’t trust them. If they fail but don’t try their best to fix it as best as reasonably possible then I wouldn’t trust them. If they fail but did their best and explained it to me, I’d be understanding and still trust them. It’s not a yes/no answer.