Oh, dear. That sounds like a sigh of something between tedium and annoyance! He must think all of this banal and beneath him-- and, she supposes, not without good reason. Someone of his standing must think everything is, and here she is, a mortal, daring to speak with him. But he's given permission to ask a question, so. Here goes:

"I've only seen the stars from the ground," Rem starts, stops, then starts again. "So a river of them...That River of Stars. I'm guessing you've been there. What is it like?"

Of course, she's assuming he has been there, but she also believes it is a safe assumption. He did say he was part of the Moon Tribe, and even in her own world, the moon is closer to the stars themselves.