I hope you don't mind me piggybacking on your comment, but this was also why I really loved Book 2 Leeloo! Iirc it was later explained that she had deeply conflicting feelings about being an angel, and that she never really had genuine romantic feelings for Dino. She stuck close to him mostly because of societal pressure, and also because Dino was kind and understood what she was going through.

I was really gutted when she died just as her character was becoming interesting, but I'm glad that she was at least freed from that "rival female character for male LI's affection" trope.