Who said "I've learned that vulnerability isn't weakness."?

This quote is attributed to Supergirl.

I've learned that vulnerability isn't weakness. - Supergirl

"I've learned that vulnerability isn't weakness."

Supergirl Strength

"I'm not just Kara Danvers. I'm also Supergirl."

"Being a hero isn't just about having powers. It's about what you choose to do with them."

"I have to believe that there's good in people, even when they give me reason not to."

"My family is what makes me strong."

"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."