Praise be to Allah.
If a fornicator repents sincerely, Allah
accepts his repentance. Allah says (interpretation of the meaning):
“And those who invoke not any other ilaah
(god) along with Allah, nor kill such person as Allah has forbidden, except
for just cause, nor commit illegal sexual intercourse and whoever does this
shall receive the punishment. The torment will be doubled to him on the Day
of Resurrection, and he will abide therein in disgrace; Except those who
repent and believe (in Islamic Monotheism), and do righteous deeds; for
those, Allah will change their sins into good deeds, and Allah is
Oft-Forgiving, Most Merciful. And whosoever repents and does righteous good
deeds; then verily, he repents towards Allah with true repentance”
See also question no. 728.
If he repents, then he may marry a
believing woman. If a fornicator repents, he should conceal his past and not
spread word of it.
And Allah knows best.