How may i treat some lesbian classmate who is a good.girl but she told me i use to be attractive.to her ??

What a compliment!: Try " Thank you. If I were attracted to girls, I'd take that as a compliment. Since I'm not, I feel a little uncomfortable knowing that. It would help our friendship if I knew you no longer feel that way." Using " I" words and stating how you feel are usually best. You both may learn something that will help you embrace diversity while respecting others' psychological space and asserting your own.