"Did it hurt?"
That time Kuma attacked Zoro was worse than anything any of them had gone trough. A lot of them had come close to death's door, but never this close. How he got so mangled and hurt, no one knew. Luffy gave up on asking after a while. Sanji would look guilty, Robin evaded answering, Brook got awkward and changed the subject. Zoro didn't answer, just stared at Luffy for a long while until replying 'Doesn't matter.' But maybe Luffy was asking the wrong questions.
"Did what hurt?"
"What happened. I know you won't tell what it was, but did it hurt?"
Zoro paused and looked away. "…Yes. More than anything I've ever lived trough."
Luffy nodded. He'd thought so…he couldn't help but feel responsible, somehow.
But Zoro wasn't done. "But it was worth it. And I'd do it again, 1000 times over."
Luffy realized the best he could do was to make sure Zoro would never have to.
