YOU SAID:

had she have known that that would have happened, she would have had more cake.

INTO JAPANESE

彼女がそれが起こることを知っていたなら、彼女はもっとケーキを持っていただろう。

BACK INTO ENGLISH

If she knew it would happen, she would have had more cake.

INTO JAPANESE

彼女がそれが起こることを知っていたら、彼女はもっとケーキを持っていただろう。

BACK INTO ENGLISH

If she knew it would happen, she would have had more cake.