I believe they make a wonderful pair. :) I mean, they are childhood friends after all and even back when they were friends they'll treat each other with greatness.
Obviously he does, Nala is his mate and queen. He loves her. that's how Kion came along. Simba and Nala known each other most likely when they were infants.
Yes. They love each other very much. You can tell he definitely
trusts her. When she tells him to get to know Kovu, he does.She even hates the idea of him getting hurt. Judging by the way she acts when he is in danger.
If he wasn't a good and loving mate towards her, Nala would have
not wanted to stay with him. She is very stubborn.