I fight her offline. My bf's is more than viable. He's good with her and I shouldn't be as bitter as I am about it. Out of all the characters, this girl has got to be the hardest one for me to read properly.
Memorize her strings. When you start shutting options down by sidestepping at the of strings, using 2P to beat 1P / 3P, and treating heichu grab strings as 50 / 50s, it forces the Kokoro player to play respectfully. She also has a good number of neutral throw punishable strings. All this is easier said than done, though.
Just so you know, heichu throw is actually a very risky move, and the hit grab is only supposed to be a 50 / 50 between the throw and a mid P which stuns; all but one of those strike followups are neutral throw punishable. If you start to toss out launchers for a guaranteed hundred or so damage when you see a heichu grab string, Kokoro players are forced to adapt. It's a game they're not used to playing.