Will God forgive the transgressions that occurred between an engaged couple after their marriage contract, or will the sin remain, despite their marriage?

The suitor is a stranger to his fiancée until the legitimate marriage contract is concluded. The completion of the marriage contract has no bearing on the forgiveness of sins. If the engaged couple overstepped the boundaries of Sharia, they must repent to Allah by abandoning the sin, regretting it, and resolving not to return to it, while maintaining discretion and not publicizing it. Sincere repentance erases sin, for the Prophet, peace and blessings be upon him, said: "The one who repents from sin is like one who has no sin." However, if they do not repent, their sins remain subject to Allah's will, unless they are shirk (polytheism), for Allah Almighty says: "Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills."