Nikki Bella knows how to sit on a fence -- refusing to close the door on her relationship with John Cena ... despite looking for her own home.
We got the WWE Diva Thursday at LAX, where she played coy about her status with her on-again-off-again beau -- whose house she's trying to move out of for her own spot.
We broke the story ... Nikki's looking to snap up her own house in the La Jolla area of San Diego.