Maybe Nathaniel didn't know as much about combat and battle as Remington, but he had certainly watched enough television and movies to know what he needed to do. He had to keep a low profile, act in secret, and work to become a champion and take everyone by surprise in the end.
"Of course I trust you," Nathaniel said, like it should have been obvious. "You're my best friend." He was pretty sure that he loved Remington, but he knew that he wasn't supposed to say that out loud. "I think we're going to the Colosseum. I think I could fight a lion if I had to. If we have to fight lions, you should let me do it."