“I'm not saying I don't want to go, I just don’t understand why I have to go alone.”
“Because it’s a singles cruise, Hobi. I’m not single, Taehyung isn’t single, Yoongi isn’t single. You’re the only one. Besides, don’t you think it would be a little strange to go on a singles cruise with a friend? Even if the friend is taken. Especially if the friend is taken.”

Namjoon and Hoseok's friends convince them to go on a single's cruise where they meet each other.