DICT.TW Dictionary Taiwan

 Sooth·fast a.  Firmly fixed in, or founded upon, the thruth; true; genuine; real; also, truthful; faithful. [Archaic] -- Sooth*fast*ness, n. [Archaic]  “In very soothfastness.”
    Why do not you . . . bear leal and soothfast evidence in her behalf, as ye may with a clear conscience!   --Sir W. Scott.