Marriage After Converting to Islam

Assalamu Alaikum wa Rahmatullahi wa Barakatuh, I would greatly appreciate your guidance regarding a matter that is very important to me religiously. I am a Muslim woman who practices Islam (I pray all prayers, fast Ramadan, and try to live according to my religion). I am considering marriage with a man who comes from a Druze background. Although he was born into a Druze family, he does not follow or practice the Druze religion and does not consider himself part of it. He does not believe in Druze teachings and does not practice their religious traditions. He believes that God is one, and he reads Surah Al-Fatiha regularly. He also understands many aspects of Islam and respects them. His family is also not opposed to Islam; for example, both his mother and father have performed Umrah. He respects my practice of Islam completely and has told me he would be willing to convert to Islam and say the Shahada in order for the marriage to be religiously valid. He is also open to learning more about Islam over time, and he has said he would be willing to fast with me, perform Umrah with me, and continue learning about the religion gradually. However, he is also honest in saying that at the moment he is not sure that he can personally affirm with full conviction that Islam is the absolute truth, and he does not yet see Islam as his own religious framework. He says he respects Islam and is open to learning more and growing in his understanding over time, but he cannot honestly say today that he fully believes everything. My question is the following: If he declares the Shahada and formally converts to Islam while still being in a process of learning and developing his belief, would the marriage be considered valid in the eyes of Allah? In other words, is it sufficient that he accepts Islam outwardly and sincerely intends to learn and grow in his faith over time, even if his conviction is not yet complete? Or would the conversion be considered invalid if he cannot say with certainty at this moment that he fully believes Islam is the absolute truth? This question is very important to me because I want to ensure that my marriage is halal and valid before Allah. Jazakum Allahu khairan for your guidance.