How is fulfilling a promise desirable, while it is a characteristic of a hypocrite that "if he promises, he breaks it"?

Fulfilling a promise is recommended, and breaking it is strongly reprehensible, but the one who does so is not sinful. If breaking the promise causes harm to the one who was promised, then it becomes obligatory to fulfill it, otherwise not. As for the fact that not fulfilling a promise is a characteristic of a hypocrite, it is one of their inherent characteristics, unlike a believer.