Must I confess my sin to my future husband if he asks me why I am not a virgin, in light of the noble verse from Surat An-Nur: "And those who accuse their wives and have no witnesses... And the fifth (oath) is that the wrath of Allah be upon her if he should be among the truthful"?

If the abomination occurred before puberty, there is no sin upon you, because the Prophet, peace and blessings be upon him, said: "The pen has been lifted from three: from the sleeper until he awakens, from the child until he reaches puberty, and from the insane person until he regains his sanity."

And if it occurred after puberty, then you repented with a sincere repentance, then repentance erases the sin.

You must conceal yourself and not tell anyone what you have done. You are not required to inform the suitor of the forbidden acts you committed, nor of the loss of your virginity, unless he stipulated virginity. In that case, it is not permissible for you to conceal its loss, but you are not required to tell him the reason.

As for the verse mentioned, it deals with the ruling of li'an between spouses if the husband accuses his wife of adultery or wishes to deny the lineage of her child.