Except in historical fiction.
'In sooth, my lords,' said Sir Bargain, as he knelt before the king, 'the Lady Mortgage caught me in her perilous web.'
(Ah, those were the days, when even evil witches were given the title Lady.)
As if the word sooth isn't magnificent enough, we have the even more heroic soothfast, too, meaning loyal and true.
'There is no sign of Bacward. Happen he will not come.'
'Nay, boy. There is no hand so mighty it could stay the soothfast Bacward.'
We must hope, of course, that the man speaking above is a soothsayer; that is, someone who not only says sooth but says things that are going to be sooth.
What's jolly clear is that, with all those wizards and dragons and odd-coloured knights about, it's a jolly nice trick if you can do it.
From The Aventures of Sir Lancelot, starring William Russell.
Word To Use Today: sooth. This word comes from the Old English sōth, and is related, rather oddly, to the Latin sōns, which means guilty.