"No problem at all!" He doesn't mind Luka having an IOU for his services. That's cool! It means he'll get to hang out with an awesome celebrity more! Plus, y'know, he did offer to help however he can.
"I've taught people how to fight, and I could teach you some first aid, but..." Teaching people medicine makes him really nervous, actually. "I don't even have to teach you anything! Let's just call it a favor. Whenever you need it." Honestly he wants to mention that he's ridiculously strong and could even do manual labor if Luka needed him to, but. That'd be a bit weird of a segue and he's trying to impress the Princess, not creep him out.
no subject
"I've taught people how to fight, and I could teach you some first aid, but..." Teaching people medicine makes him really nervous, actually. "I don't even have to teach you anything! Let's just call it a favor. Whenever you need it." Honestly he wants to mention that he's ridiculously strong and could even do manual labor if Luka needed him to, but. That'd be a bit weird of a segue and he's trying to impress the Princess, not creep him out.