"Is it because of your soulmate?" Vivi asks brazenly and everyone else around the table freezes.
"What." Zoro says, it's not a question. Sanji knows Zoro well enough to read it as a warning for Vivi to drop the fucking subject right the fuck now. If it was any other subject Sanji would kick his ass for daring to speak to a lady like that. But this is important to Zoro and though he doesn't condone this at all he's not going to throw himself in the middle. Just for this one subject though.
"Everyone knows that the moment you touch your soulmate you know that they're meant for you. It has to be skin though. So why don't you let anyone touch you? You'll never meet them that way or... or are they..." Vivi trails off, her eyes going wide as she takes in Zoro's current outfit of entirely black and she clearly starts coming rapidly to the conclusion that Sanji had.
Everyone in the world has a soulmate, it's just a fact. Somewhere out there is Sanji's and in all honesty he's desperate to meet her, or maybe him, but his money is on his soulmate being a woman. Of course a large number of people at any time aren't with their soulmate, either through not having met them yet like Sanji or that they've died like Sanji suspects Zoro's has.
Supposedly the first time that you touch your soulmate it's like being electrified, it's the pure bliss at finding the other half of your soul or in some cases the other third. Sanji has no real idea how it works for polyamorous soulmates, does their first touch feel like getting part of their soul or are they destined to all bump into each other at the same time? Either way it fills that gnawing emptiness that chews at the edge of the mind of everyone who hadn't met their soulmate yet. Sanji dearly wants to find his, both to scratch that itch that he can't do on his own but also so that he can find true love and he's a romantic at heart.
People go about it differently of course, some people like him flirt with and make contact with as many people as possible in the hope of upping their odds of finding that one person. Some people like Usopp just carry on as normal, figuring that fate will take its course. Then there are those lucky few like Nami and Luffy who literally are thrown together.
Nami and Luffy are an unusual case, there aren't all that many platonic soulmates out there but the pair of them are just that. They're certainly not unheard of but they are rarer than the romantic kind. Sanji has no idea if it's because one or both of them has no intention of having sex with anyone or if the people they eventually end up with romantically won't mean as much to them as they do to each other. Still, the way that Nami fits with Luffy's exuberance, the way that she balances him out with her rationality but also backs him up absolutely warms Sanji's heart.
What makes Sanji's heart chill though is Zoro. Zoro is a little young to have met and lost his soulmate. Perhaps they were childhood sweethearts tragically cut short. If the itch of not knowing his soulmate bothers Sanji he can't imagine what it must feel like to have that filled and then ripped out. Plenty of soulmates who lose their other halves die at the same time or right after from the shock or the grief. Bringing it up to Zoro must hurt like hell.
"I don't want one, not that it's any of your business." Zoro growls out in his darkest tone of voice.
Everyone in the room looks shocked. Sanji's brain trips over the idea, turning it over in incomprehension. How could anyone not want to find their soulmate? It's one thing not to go out actively looking for them but to avoid finding them is unthinkable. If Zoro doesn't want to find his then his clothes instantly make sense. Zoro is avoiding touching anyone at all, he could run right into his soul mate and as long as they didn't touch his face neither of them would ever know that they met. Holy shit.
"How can you not want to meet your soulmate?!" He yells out in shock and Zoro turns his hot glare on Sanji.
"I can't afford to." Zoro answers waspishly.
"I have a dream to achieve and I can't do it if I'm distracted or tied down by someone else. I don't want them, whoever they are." Zoro says with a haughty expression on his face as if that decision makes him better than them.
"That's... that's the dumbest thing I've ever heard!" Sanji snarls, leaping to his feet. His chair bounces on the wooden floor behind him at his sudden movement.
"It's not dumb!" Zoro yells back, getting to his feet as well.
"Yes it is! Your soulmate supports you, they're your other half, and they help you, they don't make things worse!" He shouts, his fists clenching on the table top. Zoro snorts at him mockingly.
"Okay Sanji, your dream is to find All Blue isn't it?" Zoro asks with a tilt of his head.
"You know it is." Sanji says darkly, what the fuck is Zoro getting at here?
"So what if you met your soulmate and she couldn't stand the sea? What if it made her sick? Would you drag her out onto the sea to find All Blue with you?" Zoro asks and Sanji's jaw drops. That would... that would never happen.
"Or what if she had something tying her to where she lives? So she can't leave with you. What do you do? Would you leave her like you never met her even though it's hard finding the same place twice out here or that you could die before getting back to her?" Zoro presses him.
"That's- no. I wouldn't look for my soulmate my whole life just to leave her." Sanji says unhappily and tries to ignore the way that Usopp flinches, he remembers too late that what he just described was Usopp's parents situation. Still, he's telling the truth, he wouldn't do that.
"So, which would you do then? Would you give up on your dream just to be with your soulmate or would you drag them onto the sea? One of you would end up miserable and bitter for it and you'd lose a dream." Zoro says darkly.
"You don't know that would happen! Your soulmate is perfect for you, it's the definition! My soulmate would be happy for my trying to find All Blue, they would want something like it too!" Sanji argues back.
"You can't be sure of that. I'm not risking my dream for that." Zoro says with a shake of his head and one horrible part deep down in Sanji admits that though Zoro is wrong through and through his argument does make logical sense.
"I feel sorry for your soulmate." He spits because it's the only thing that he can say.
"So you marry them then, I don't care." Zoro answers with a careless shrug and walks off.