Despair?

"I will not seek it," the other replied.

"It has been opened once and it is enough. And you,are you sure that man can conquer until he has been wholly defeated? Are you sure that he can find plenitude till he has known utter despair? You will not let him despair of himself, but it may be that only in such a complete despair he finds that which cannot despair and is something other than man."

Shadows of Ecstasy - Charles Williams / ch.11