Who said "A warrior's greatest opponent is his own doubt."?

This quote is attributed to Zoro.

A warrior's greatest opponent is his own doubt. - Zoro

"A warrior's greatest opponent is his own doubt."

Zoro Faith

"I am not going to die. I'm going to keep fighting until I become the world's greatest swordsman!"

"Shitty glasses."

"I don't care what the world thinks. I'm going to be the world's greatest swordsman!"

"A swordsman's true path is one of solitude."

"Faith guides me through difficult times."

"Faith is believing when you can't see."

"You have to believe in something, or you'll fall for anything."

"Faith in God and in each other is what sustains us"