Who said "A man cannot be comfortable without his own approval."?

This quote is attributed to Mark Twain.

A man cannot be comfortable without his own approval. - Mark Twain

"A man cannot be comfortable without his own approval."

Mark Twain Strength

Novelist American 1835–1910

"The secret of getting ahead is getting started."

"If you tell the truth, you don't have to remember anything."

"The man who does not read has no advantage over the man who cannot read."

"Kindness is the language which the deaf can hear and the blind can see."

"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."