Promise facts for kids
When a person agrees to do something or to not do something, that person is making a promise. A promise can be made verbally (by saying it), or it can be written down as a contract. Breaking a promise, or not keeping it, is often just bad manners, but it can sometimes be illegal, such as when a contract is not kept.
A vow is a special promise. It is mostly used in a religious sense or in ceremonies such as marriages when the couple who are being married make their "marriage vows", promising to be faithful to one another.
Promise Facts for Kids. Kiddle Encyclopedia.