Who said "Killing is easy, living with it is the real test."?

This quote is attributed to Joker.

Killing is easy, living with it is the real test. - Joker

"Killing is easy, living with it is the real test."

Joker Philosophy

"Everything burns."

"Do you want to know the funny thing about all your big plans? They don't matter."

"The only sensible way to live in this world is without rules."

"Madness is like gravity - all it takes is a little push."

"I've seen the worst humanity has to offer."

"Sometimes I wonder if the world is worth saving."

"Every choice shapes our destiny."

"Order is the foundation of a good life."