One Piece Chapter 31, page 17: THE TRUTH

With blinding speed, Sham lunges forward and clashes his claws against Zoro's swords with a loud "KA!!". Zoro is caught off guard and pushed back, gasping, "YOU...". Sham smirks maliciously, revealing his deception: "YOU MUST BE THINKING... THAT I'M JUST A COWARD? I WAS JUST PRETENDING TO BE A COWARD. IF I DIDNT, THEN YOU WOULDN'T HAVE LEFT YOUR GUARD DOWN!"