He was so insecure and blinded by h

He was so insecure and blinded by his attraction to the Dark side that he imagined she would find it impressive if he bec ame a real Death Eater. Ironically, Lily might have grown to love Snape romantically (she certainly loved him as a friend) if he had not loved Dark Magic so much, and been drawn to such loathsome people and acts. When Snape called Lily a"Mudblood" in a moment of humiliation, it was the last straw for Lily. When she later asked him if he still intended to become a Death Eater and he did not deny it, she severed all ties with him, despite Snape's profuse apologies. At this moment, there is just regrets accumulated in Snape's heart, yet later when Snape made the worst decision in his life, he was filled with the senses of guilty.