Should a girl marry a man she has feelings for and a history with, despite his weak religious commitment, especially if her Istikhara and dreams suggest positivity? She has repented and seeks a partner with strong Islamic values but struggles to let go.
She should consider that the most important criteria for a good life partner is religion and manners. Weak religious commitments can lead to possible dangerous results in the life especially after few years. What can stop him in the future from looking for other affairs if his religious commitments are weak?
I don't advise her to marry a person who is weak in his faith and religious practice even if she has feelings and history with him. The feelings will never remain for long if there is no authenticity in faith and trust in religion.
Wassalam.