Sanders is not my favorite.  I find him to be a loose cannon, in some ways reminiscent of Donald Trump in terms of being a maverick and not following established rules.  I get a sexist vibe off him as well.  However, if he is anything, he’s principled, and in a he-said / she-said contest between Sanders and Warren, I believe Sanders.  Warren I find generally slippery and very capable of bending and stretching the truth.  Did Sanders say something about the difficulty of a woman winning president?  Probably.  Did he say what Warren says he said and he denies?  Highly doubtful.  I think it’s about as true as it is true that Warren is a Native American who did not benefit from claiming said ancestry when hiring on at Harvard.