A promise made is a debt unpaid.
She had made a promise to herself that she intended on keeping. She was never going to go out with another writer: no matter how charming, sensitive, inventive, or fun they could be. They weren't worth it in the long run. They were emotionally too expensive, and the upkeep was complicated. They were like having a vacuum cleaner around the house that broke all the time and only Einstein could fix it. She wanted her next lover to be a broom.
The best way to keep one's word is not to give it.
He that promises most will perform least.
Magnificent promises are always to be suspected.
Promises and pie-crust are made to be broken.