The Bel's can be an obnoxious fight to grind up for. I remember the last 3 or 4 battles I had to grind 8 to 10 levels in between, in the first DS. And just when you thought you beat it, you didn't. Check out Persona 3:FES and Persona 4, when you can. P4 is more popular with the main stream, but P3:FES is far better, in my opinion.
I have yet to play DS 2. How is it? I seemed uninteresting when I read descriptions when it was first confirmed.