What does the cryptic crossword clue "Promise not to be unfaithful again? (7)" mean?

The definition is "Promise not to be unfaithful again?". The wordplay uses a cryptic definition. Cryptic definition The answer is REMARRY.

Promise not to be unfaithful again? (7)

Independent Cryptic #11635 | 4 Down | 2024-01-25 flower