Is it obligatory for a young man who committed fornication and then repented to inform his future wife about what he did previously, given his fear of scandal and her rejection of him, knowing that the consent of both spouses is a condition for marriage?

Sincere repentance erases what preceded it. The conditions for sincere repentance (tawbah nasuh) are: regret over the action, a firm resolve not to return to it, and abandoning the sin. It is not permissible for a Muslim to disclose the sin he has committed, for Allah Almighty has concealed it. Disclosing it is considered a lifting of Allah's concealment and a spreading of indecency. Umar (may Allah be pleased with him) forbade a man who wanted to disclose the mistake of his former freedwoman before her marriage, saying to him: "Had you disclosed it against her, I would have punished you."