The term 'promise in marriage' is often referred to as betrothal, which is a 7 letter word. Betrothal is a formal agreement between two people to marry each other. It is usually done in the presence of witnesses and is considered legally binding. In some cultures, betrothal is a part of the marriage ceremony itself. Betrothal is an important part of many religious ceremonies and is seen as a way to ensure that the couple will remain faithful to each other.