Is marriage destined for a person from birth, and if so, how can supplication change this destiny to facilitate marriage to a specific person?

Allah ordained destinies fifty thousand years before creating the heavens and the earth. Everything is predetermined and inscribed in the Preserved Tablet (Al-Lawh Al-Mahfuz), and it does not change. However, what is in the angels' scrolls may change due to an act of obedience, disobedience, or supplication, in accordance with the Almighty's saying: (Allah abolishes what He wills and establishes [what He wills], and with Him is the Mother of the Book) [Ar-Ra'd/39].

If your affection for this person arose from a prohibited cause, then repentance and severing the relationship are obligatory. However, if it was without a prohibited cause, there is no blame. Nevertheless, excessive thinking about him increases attachment and may lead to prohibited acts. The advice is to pray for a righteous husband, as this young man may not be suitable, and compatibility may not occur even if both individuals are righteous, as happened with some Companions.