That's IMPLIED by her final choice and her storylines in Onigashima
Gosh..
But... omg..zen
I'm not saying that she doesn't want to leave with the crew.
I'm saying that there are TWO desire here. One desire, to sail the sea, because she was thaught (by her experience and childhood and Ace) that the sea would be the resolution of all her problem of Freedom and ANOTHER desire which came during Onigashima that is to be here for the sake of the Kkozuki as a Samourai and for Momo.
The two desire just like Vivi at the time were cohabitating in Yamato's mind until she made her final choice FREELY (and offscreen granted)
The point of the entire arc is FREEDOM. The freedom to choose the path you want and not the path that is chosen for you by your dad or your idol.
This is a beautiful message and its really saddening to see that you guys completely missed it.