Who said "A man must sometimes stand alone to find himself."?

This quote is attributed to Theon Greyjoy.

A man must sometimes stand alone to find himself. - Theon Greyjoy

"A man must sometimes stand alone to find himself."

Theon Greyjoy Solitude

"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."

"Sometimes being the best means being the loneliest."

"Solitude gives us time to reflect on what matters"

"I'm not good with people, never have been."

"I feel like I'm disappearing."