Who said "A swordsman's true power lies in his conviction."?

This quote is attributed to Zoro.

A swordsman's true power lies in his conviction. - Zoro

"A swordsman's true power lies in his conviction."

Zoro Strength

"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."

"Strength comes from within."

"A woman should be proud of who she is."

"A strong woman can overcome anything."

"The only thing I'm good at is killing."