I'm not exactly sure Dracula feared anyone. When he was killed by Richter and Juste, he didn't seem to think much of it. And he brought up a good point. Why should he when he's just going to come right back? And he's frequently laughing through entire fights with the Belmonts.
Also, other people can kill Dracula, too. Perhaps too many other people
Anyway, playing Lament of Innocence and Dracula's Curse would help answer your question. The Belmonts have a special weapon that is very effective against him and his minions, and they've vowed to hunt and kill him, which, they eventually did, many times.