Kris Humphries -- New Girl Looks Like Kim Kardashian ... from a Certain Angle

If you were just looking at her ass, you'd swear the girl hanging with Kris Humphries on the beach yesterday was his ex Kim Kardashian. But from the front ... she's NO KK. Not even close.

Kris and the mystery brunette were spotted in Miami, but when they got wind of the photogs ... they quickly went in separate directions. A sign of new love?

Sources close to KH say, no -- the chick is just a neighbor who happened to sit down next to Kris ... but they're not dating.