Who said "To be tested is to be made strong."?

This quote is attributed to Theon Greyjoy.

To be tested is to be made strong. - Theon Greyjoy

"To be tested is to be made strong."

Theon Greyjoy Courage

"I am the Prince of Winterfell. I have no need to prove myself to anyone."

"What is dead may never die."

"You can't marry her. You're promised to me."

"I'm a Greyjoy. We do not sow."

"Never let fear stop you from chasing your dreams."

"Courage is being afraid but doing it anyway."

"Sometimes you gotta do what you gotta do."

"Sometimes you have to be the monster to stop the monsters."