"Does it hurt?" he asked at last.
"Of course it hurts," she said. "It's meant to hurt, Anything that's worth achieving has its price. And, by corollary, if you are prepared to pay that price you can achieve almost anything. In this particular case I am paying with physical pain. Hans Andersen's little mermaid wanted legs instead of a tail, so that she could be properly loved by her Prince. She was given legs, and by inference the gap where they join at the top, and after that every step she took was like stepping on knives. Well, what did she expect? That was the penalty. And, like her, I welcome it. I don't complain."
Fay Weldon: The Life and Loves of a She Devil (1983).
The context is cosmetic surgery.