"But Mommy/Daddy, you promised!" When your kids whine those words at you, do you cringe because you know you reneged on some promise you made them and they just caught you at it? Okay, I know that when you are a single, divorced parent your life is all upside down and the responsibility of getting your kids moving in the right direction sometimes involves gentle or subtle manipulation-via-promises just to motivate them. I'm urging you not to go in this direction.
Your children remember every single promise you make to them. Because they haven't learned to reason yet, they have a tendency to live in their feelings - their emotions - and these emotions create brilliant visualizations of what you've promised them: an ice cream treat; a trip to the park; some toy they really want. They can see it in their mind's eye, because their mind created it for them.
And to that they have added "trust" because their daddy or mommy said it and they implicitly trust you. And they expect you to DO what you said you would do. You don't want to destroy your child by making idle promises, so only make those promises when you fully intend to follow through all the way.
Your children can learn wonderful lessons when you keep your promise to them. They can learn to trust, to love, to be secure, to be safe, to reach their potential. But if you try to side-step what you promised, your children can be affected in a negative manner. They can experience anger, disappointment, depression, helplessness, and distrust. You certainly don't want those results, so consider keeping the promises you made them.
What does "I promise" mean to you? To me, it means "I intend to follow through and do what I'm saying to you." And then I do it. My kids could always trust me to tell the truth to them and they could trust that my word was worth something. I wanted their words to have value and trust, too. So, if you keep your promise, they can count on you. If they keep their promise, you can count on them.
You have to mean the words you say, and only say them when you fully mean them. Here's another aspect of promise-keeping you might not have considered: "Tommy, wash your hands and come to the table to eat." He doesn't do that. You say it again "Tommy, wash your hands and come to the table now." He ignores you. "Tommy, I said come to the table right now. If you don't, I'm going to (insert your promise here). I know this from deep within myself that if you keep your promises in other areas, your little boy is rushing off to the bathroom to wash his hands.
And here's a word from the wise who've been there: there is more meaning and more conviction behind what you said the third time than what you said the first time. If you could weave more meaning and conviction into your promise, make sure you have his full attention (a touch on the arm works) and then deliver the promise, you'll only have to say it to your kid one time.