So what specifically are you having trouble with? Do you have trouble dodging the boar? Are you having a hard time landing your sword on Bulbin?
*shrug* Keep trying? I remember I died a lot at that part too. The goal itself is pretty simple and straightforward, so I'm not really sure what sort of "advice" I could give. Just weave around to avoid him, and try to stay close to him while you do it so you can slash him.
Also, it's not jousting because they're not using lances. >_>
If I remember right, I moved out of the way at the last second as he was charging at me. it's like a game of chicken, don't move until the last possible second. If you move too soon, he sees it and readjusts to still hit you. Once I got the timing right, it wasn't as bad.
"You empty-headed animal food trough wiper!" ~ a soldier in DQ IV DS