[quote="Fozz"]They fell in love because it is the nature of animals. Simba hadn't seen anyone from his species in a very long time, not in his adolescence and not since then. Then he suddenly met Nala again, who was a flirty friend when they were little cubs.
Animals (and humans) have a strong desire to reproduce, and that desire consists of sexual attraction. And when they haven't seen one of their kind in such a long time, they will probably be attracted pretty quickly. That also explains why Mowgli suddenly fell for Shanti at the end of Jungle Book.
I just realized that I've only explained Simba's side of it. As for Nala, I don't think there were many male lions at Pride Rock who were close to Nala's age (Scar was much older, and Nuka was a cub), so I think that explains her affinity for Simba.[/quote]
I agree.