Think about the one thing you've never told anyone, the version of the truth you keep folded up small enough that it never has to see daylight. Now imagine handing it to someone else. Watari wouldn't blink, wouldn't ask why, he'd just quietly make sure it stayed safe forever. Soichiro would take it seriously enough to actually help you carry it, even when the honest thing to do was the hard thing to do. Matsuda would show up flustered and sincere, more worried about you than about the secret itself. Naomi would want to understand every piece of it, carefully, so she could actually protect you instead of just comforting you.
Trust isn't really about who's the smartest person in the room. It's about who you'd actually hand this to, at 2am, with no one else watching.
Fifteen questions in, you'll know.
