"Now be sincere; did you admire me for my impertinence?"
"For the liveliness of your mind, I did."

– Jane Austen

Pride and Prejudice, Chapter 60. If you want to know what attracted Darcy to Elizabeth, it’s all here. Elizabeth is a woman of high intelligence and quick wit who can hold her own with anyone. Darcy admits that it was her lively mind that he fell in love with.