Shaykh โAbd ar-Rahmaan as-Saโdi (may Allah have mercy on him) said: What this verse means is that if a person commits zina, man or woman, and has not repented from that, then the one who wants to marry him or her even though Allah has forbidden that, must be:
either one who does not adhere to the rulings of Allah and His Messenger, and such a person cannot be anything other than a mushrik; or if he does adhere to the rulings of Allah and His Messenger, but he wants to marry this person even though he is aware of her zina, then this marriage itself is zina, and the one who wants to get married is an adulterer and unchaste. If he truly believed in Allah, he would not want to do that.
This clearly indicates that it is haraam to marry a fornicatress or adulteress unless she repents, and it is haraam to marry a fornicator or adulterer unless he repents.