User blog comment:Ghmorello/Chapter 845: Bride Over Pride/@comment-30422587-20161105091819/@comment-53539-20161105194611

Seastone is hard to get hold of outside of the WG, as they pretty much have control over it. Unless your an ally of them I doubt you'll get the stuff.

Even there, there are a number of Devil Fruit users with Big Mom... :-/

I don't thin Sanji is giving up as much as he can't see a way out right now. He knows too well what his family are like and he knows Big Mom is a Emperor... I don't think its a simple case of he has given up, its a case of he feels his freedom he thought he always had has now been taken away. Also, he is clearly not happy and would likely jump ship so to speak, he is surrounded by family who hate him and he hates them... In a forced marriage he can't get out of and has to go through. Though he likely thinks "at least she is cute" right now. :-/