The marital insurance certificate between husband and wife usually refers to that during the life of husband and wife, one party has fault behaviors, such as extramarital affairs, drug abuse, gambling, domestic violence, etc., because the behavior is exposed or the relatives and friends exhort, in order to save the marriage, they admit their mistakes and make "voluntary divorce if committed again", "property belongs to the other party", "give up the custody of children", "give economic compensation to the other party" And other written commitments. For this type of guarantee, the court finds different situations due to different contents. The letter of commitment is actually a kind of contract, of course, it has legal effect, but a valid letter of commitment must meet the following three conditions at the same time:
 1. It is a reflection of the true will of the parties. The content of the letter of commitment shall be the expression of the true intention of the parties, and shall not be forced or threatened or lured or deceived.
 2. No violation of relevant laws and regulations; The content of the letter of commitment must comply with the provisions of the law and must not violate the prohibitive provisions of laws or administrative regulations, otherwise the letter of commitment may become invalid.
 3. It does not infringe upon the interests of others. The promisor can only dispose based on what he has the right to dispose of, and cannot infringe upon the legitimate interests of others.
 Legal basis
 Article 465 of the Civil Code of the People's Republic of China [Effectiveness of legally established contracts] A legally established contract is protected by law.
 A lawfully formed contract is legally binding only on the parties, except as otherwise provided by law.