Ask him what his name is
From Create Your Own Story
"So, what's your name?" you ask, starting to like this guy.
"Sam," he replies, beaming. "Can I... put my stuff somewhere?"
"Oh, of course!" you return, blushing. You hadn't noticed that he'd been holding his things since he entered the room. "That's your room, in there."
You point to the room that you had expected a female to inhabit. He goes into it and closes the door, with a "Thanks."
A male roommate, huh? This could be fun....