I'm thinking to get Dedicated IP for my Shared Hosting (I'm running wordpress on shared hosting). Will it be beneficial for me? Above all, my shared hosting won't misbehave after i get it?
Certainly get it if you can afford it. No matter if it is shared or shared-reseller hosting (where you can assign your dedicated ip as your own shared ip for your websites).
It will make your websites more independent, especially if you use self hosted e-mail system on your shared hosting. Like Fahad said, there are IP blacklists, and when some bots hack weakly protected websites or flood their contact forms with spam the IP usually gets blacklisted soon after and all the websites which use that IP suffers from that.
You asked if it can break / misbehave something - yes it can, but its all solvable, if you know your stuff (changing DNS settings, etc) . You can always revert back to your shared IP, if you feel you are getting in too much trouble.