Miyeon is your sister's best friend and only your sister knows that you like Miyeon and she always ships you with her but she never told Miyeon

You are in the bathroom downstairs while your sister is upstairs in her room doing her makeup. You hear the doorbell ring and when you go open it you see Miyeon there with her cold look

Miyeon: "Hi. Is your sister at home or is she out?" she says with her cold voice as she looks you up and down