Customs vary somewhat from one country to another. Also, individual attitudes vary within a country. One possibility:
Me: You have really nice hair. It's pretty.Being a North American speaker, Soup would know that "Thank you" is the expected response to a compliment. (Nothing more is required.) If an American would say to a Chinese girl, "Gosh, you're really pretty" and she said, "No, I'm really ugly" the American probably wouldn't know what to say, but he might be put off by such an odd (to him) response.
Soup: Thank you.
Me: You're welcome.