Donald Sterling's New Lady -- WE'RE NOT DATING ... I Just Work For Him!

She's been out to dinner with him ... on weekend trips with him ... and even street fairs together -- but the new lady on Donald Sterling's arm tells TMZ Sports she's NOT dating the billionaire.

Her name is Raven -- and she was out in L.A. yesterday when she made it very clear her relationship with Donald is strictly professional ... not romantic.

"We're not in a relationship, hes a married man."

Raven says she met Sterling through V. Stiviano -- and despite the fact she's a designer and has experience in fashion, she's now helping Donald run his business affairs.

But Raven says she's not looking for a free ride -- telling TMZ Sports there are times she cracks open her own wallet when the two hit the town.

Check out the clip.