it is the middle of the night and Frisk is almost ready to go home to bed, she gets ready for bed and she lays down and once she closes her eyes she hears a noise down stairs, she quickly goes down to see and she sees you in the living room, she could only think as if this was either real or a nightmare.

Frisk: "Who are you?"

She asks you as politely as she can, she was scared but she didn't want to show it.