Ask him why

You shake your head in disbelief. "Why would you do this? Why make a fool out of me?" You start to pull your shorts back up, but he catches you by the arm.

"I wasn't trying to make a fool out of you," he says. "It started out like I said, as a test. I needed to know if I could trust you. And then I saw the shower, and you were so kind, and... and it's been a very long time since anyone was kind to me." He sounds so sad, so lonely and ****. Of course, that might be an act, too, but you don't think so.

"What about your 'mission'?" you ask, not yet willing to fall for another of his lies. "Or was that a load of shit, too? Did you just come here to get laid by the first idiot human you could find?"

"No, what I said is true," Luke says. "My team came here to gather information, but we had to abort the mission when the police showed up. They went back through the portal; I'm trapped until they can come back for me. I'm alone in this strange universe and, frankly, I'm scared to ****. I shouldn't have tried to trick you, and for that, I am truly sorry. But I'm not sorry I was able to get you out of your clothes. You are a fine looking human."

"You are incorrigible," you say, fighting a grin as you shake your head again.

He grins back at you, unabashed. "Guilty as charged. But the real question is, am I fuckable?"