Not to shit on anyone's beliefs....but Mantei is deeply religious. So it seems to me it's pretty easy for him to have faith in something he can't see.
The majority of us would immediately be suspicious because most of us wouldn't do a lengthy online relationship (besides with one another). But you can't think like us, you have to think like him.
You spend hours of your everyday life talking to someone and supposedly falling in love with them sight unseen. That continues for a long time. So when things fall through like the personal meetings, etc. do you give up on it? Everything we've been sold about Mantei would say he's not that type of person. He wanted to believe in this girl and what he thought they had built so far. He's gullible and naive as shit. He admitted he knew people would make fun of him and think he's crazy if he told people he hadn't met her. I'm not saying any of this right, but I don't think he was in on it...he's just a naive, or dumb, or a believer or a hopeless romantic. We'll see. Because if he was it will definitely come out.
There are already stories that this Tui kid has also done this to others.