Well...if its a one off...I'd have to say Ronda...mainly because
Charlotte would not loose anything by dropping a match to
Ronda.
I'm kind of hoping they do 3 matches...Wrestlemania 35,
Backlash & Money in the Bank...or maybe Wrestlemania,
Money in the Bank & Extreme Rules next year...but no
matter what happens...I think it will be an awesome moment
for women's wrestling & both of their careers.
Personally I wouldn't be surprised if they begin building to
it as soon as SummerSlam with Ronda defeating Alexa &
Becky winning the SDL Championship.
Leave Charlotte without a belt for a few months while Ronda
takes down most of the RAW roster...then have Charlotte win
the women's rumble & openly challenge Ronda as Asuka did
to her.
But who knows at this point.
Knowing how WWE usually treats people with talent, I wager that Charlotte will win the first bout to aggravate the fans and make them want Charlotte to be bested in a rematch. They did that to Lex Luger at Summerslam 1993 and hadn't he revealed that he was going to be made the next champion, he'd have won the world title, but because people found out beforehand, they had to change the finish and let him put Yoko over so Bret Hart could win the belt instead.
Of course, in today's age, people aren't nearly as reckless as the likes of Luger, so, if all goes smoothly, Ronda Rousey should be triumphant in the second fight with Charlotte, having lost to her by pin fall or winning her first match with Charlotte via DQ. Such is the way of the WWE. Never put someone over the first time because a second chapter in the battle will draw better ratings. That company has an annoying gift for shortchanging people, either in the short term, or the long term, depending.