At Last-Rihanna & Drake Now Dating For Real

TMZ reports that multiple sources extremely close to the couple told them that they've gone from casually hooking up to seriously dating ... they've decided to give it a serious shot.

We're told Rihanna wants to spend as much time with Drake as her schedule will allow -- because he treats her better than anyone she's ever been with. Not a high bar.

As we reported, the pair have been virtually inseparable while Drake's been touring in Europe -- we're told Rihanna has spent every single night with him since she arrived.

As for Drake, he's smitten -- one source said "he's in the best mood he's been in a long time."

 See pic of the couples together after the cut ...