WWE Diva Nikki Bella -- I'm Getting in the Real Estate Biz

WWE Diva Nikki Bella is about to become the hottest real estate agent ever ... but don't worry wrestling fans, she's not quitting her day job.

Nikki's been taking prep classes at a San Diego real estate school to get prepared for the licensing exam -- and her classmates say she was super down to earth.

We're told Nikki has no intention of leaving wrestling anytime soon ... she's just trying to make some extra dough on the side during breaks.