[How to tell her he wouldn't have sided with 'those people' if he'd known he still had a chance with her? If he'd ever had a real chance with her?]

Why do you have to be so very... Gryffindor? I'm Slytherin, Lily, this is who I am. These are my people, and we... we are better. That is how the world works. You end up with another Gryffindor like Potter, and I end up alone, but with others like me. I'm a part of something with them, and my talents for the dark arts are appreciated there.