vow

a very serious and formal promise

the last in a series of promises, often in a religious context

a promise not to speak, often for religious reasons

to promise that you will not do something again

typically used for two people getting married

to fail to keep a promise you have made

to fulfill a promise you have made

to repeat marriage vows, often on an anniversary

used to specify the nature of the vow, e.g., a vow of silence

to make a promise to someone (often to oneself)