It's tough to call. Leslie has a shit record against top 10 competition (Kaufman twice, Eye, Honchack) and Rin only lost to Miesha but has a long list of wins where the best names you'll find are past prime Tara LaRosa and Sarah D'Alelio, and that record has been heavily questioned as she has been given favorable rules by Pancrase (against Danielle West, for example, she was allowed to knee her opponent but not to be hit with knees).
I'm picking Rin, but my guess is close to 50-50 and wouldn't disagree to her being a slight underdog to Leslie.