This Super-Buff Ballet Dancer Used to Date Rob Kardashian, But Who Is She? (PHOTOS) 2 of 2 Prev Autoplay View Gallery Tweet November 6, 2012 at 06:41PM EST by Chako Suzuki Related: The Kardashians, Relationships , Rob Kardashian Jr. , Guess Who? full size Credit: Instagram It's Rosa Acosta, Rob Kardashian's Former Fling! The racy photo-oversharer is Miss Rosa Acosta, video vixen, ballet dancer, and former Rob fling. Did you get it right? Want more? Play more "Guess Who?" here! Can’t get enough Kardashians gossip? Like us on Facebook or follow us on Twitter!