Who said "Strength is not only in weapons, but in conviction."?

This quote is attributed to Missandei.

Strength is not only in weapons, but in conviction. - Missandei

"Strength is not only in weapons, but in conviction."

Missandei Strength

"I am Missandei of Naath, interpreter and advisor to the Dragon Queen."

"Daenerys Targaryen chose to free us, not because she needed us, but because it was right."

"Knowledge is power, but wisdom is knowing how to use it."

"I have served many masters, but I chose to serve the Mother of Dragons."

"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."