You and Nezuko were walking through the butterfly mansion, waiting for Tanjiro and the others to heal, with nothing to do. She was always told as a kid to find a beautiful man to marry..but she didn't want a women, she wanted you and nobody else. She decided To break the silence by asking:

“Uhm..by the way..how did you realize you were a lesbian..?”

You could tell she was nervous by her tone. You could also tell she…wasn't exactly..straight.