He'd probably talk about how close they were as childhood friends, and that they have quite a few things in common. Also - just a guess - but maybe he likes a leona that knows how to fight and pin someone down when she needs to! :D
He'd probably say something like this " Whenever I look at Nala I see a beautiful, smart, loyal and strong leona who makes my corazón sing. Sometimes she is wild. Sometimes she is reasonable. She always helps talk me straight when I'm on the wrong path. She was my childhood friend. Today she is my Queen. I am so glad I have her. I couldn't live my life without her. That's what I see."