Seeking Guidance on a Matter of the Heart

Assalamu alaikum, brothers and sisters. I've been turning something over in my mind and really need some sound, grounded advice from those with knowledge. My aim in life has always been to follow the Qur'an and the Sunnah to the best of my ability. I don't lean towards any particular group; I just try to be a simple Muslim doing the right thing. Lately, I met someone whose character and sincerity in her Deen really impressed me. Of course, the topic of marriage came up, but there's a bit of a complication: she's from the Ismaili (Aga Khani) community. When we talked about it, she said something that gave me both hope and pause. She expressed that after marriage, with all her heart, she would adopt the practices of Ahl al-Sunnah, purely for the sake of Allah. However, because of her family situation, she can't openly renounce her Ismaili background or their concept of Imamat. We're both thinking ahead. Our plan is to marry in about five years, insha'Allah, giving us time to mature and, importantly, to try and get our parents and families comfortable with the idea. So my question is, from the perspective of the Qur'an and the authentic Sunnah, is a marriage like this considered permissible? How should someone navigate a situation where a person is genuinely willing to practice Islam sincerely but feels they can't fully step away from certain beliefs because of family ties? I'm looking for honest, Islamic guidance, not just emotional takes. Jazakum Allahu khayran for your help.