Is it possible for someone to get your World of Warcraft account password by only knowing your characters name and server A.K.A realm

No, that is not possible.

First you'd need to find the specific email used by a person for that account, which (if the person is smart) is used only for WoW. Second, since users choose their own password, it can be as complicated as anything.

Character and server have nothing to do with it, since without the person telling you this info, there is no way to connect character/realm with an account.