[Muffet briefly considers all the potential avenues by which one might attempt to comfort a clearly tired and hurting stranger, and decides on the option she feels least likely to be trite or insulting: blunt (if sympathetic) honesty.]

That sounds horrifically depressing. I'm sorry.

[Well, at least it's genuine. She moves on briskly, trying to offer him something else to focus on without making it uncomfortable by saying so outright:]

So, what else did Sans tell you about the Underground? It's a rather complex place, I'm not sure exactly how much he would have covered- particularly if he was in the mood to be lazy.