
Henry I. answered 03/21/19
Experienced, Patient Math and English teacher
"Your faithfully" or the related "Your faithful servant" are formal closings from the 18 century and before. They are virtually never used today in the United States. If you are elsewhere, the custom might be different. "Yours sincerely" or "Sincerely yours" are common, relatively formal closings appropriate for most settings, except communications with good friends.