Considering Islam for my spouse, how can I find faith in Allah?

Assalamu alaikum. My wife and I have been married for six years, and from the start, she has mentioned that for us to truly share a life together, I would need to embrace Islam. I’ve never really been religious-I’m a physicist by trade, so my views often clash with religious ideas, but I try to stay open-minded. Science doesn’t have all the answers anyway. Lately, she’s grown much stronger in her faith and said she can’t continue our marriage unless I sincerely believe in Allah and accept Him in my heart. Just going through the motions of practice isn’t enough anymore. That hit me hard; I was devastated because I love her deeply and always pictured our future together. So I’m starting this journey-maybe it began for love, but I genuinely want to learn and possibly find my own faith. My big question is: what makes you completely certain that Allah exists? And how do I even begin from scratch, with zero religious background? Also, is being a true Muslim just about believing in Allah, or is following His teachings and ideals enough? Jazakallah khair for any advice.