Sans knows all about finding it difficult to face things head on, too. They're probably more similar than either of them realize. Sans spends a long time hesitating before eventually saying something.

"...I spent so much time lying to him back home, now that I've been trying to come clean..." He trails off. Part of him wants to be mad at Papyrus for this, but he knows that's not even remotely fair.

"I guess it's just getting pretty obvious that he actually doesn't know anything about me. Which is... one hundred percent my own fault." Its hard to read his expressions, but he seems more like he's grimacing than grinning at the moment. "Guess it's starting to feel like maybe it'd be easier to not bother."