Green’s Dictionary of Slang

(orig. US black) yes indeed.

1887		G. Devol Forty Years a Gambler 145: Laws golly! if dis old nigger hasn’t done gone and lost his eyesight, sho ’nuf.
1890		‘F. Anstey’ Voces Populi 47: She’d ha gien ’em all a proper doin’, sure ’nough!
1899		C. Chesnutt ‘Sis’ Becky’s Pickaninny’ in Conjure Woman 156: Finally dis yer man ’lowed Sis’ Becky wuz gwine ter die, sho’ ’nuff [Ibid.] 157: So sho’ ’nuff, Kunnel Pen’lton sont de hoss back.
1899		F.E. Daniel Recollections of a Rebel Surgeon 218: You are a greeny, shonuff.
1920		H. Wiley Wildcat 184: Sho’ nuff. Sho’ sounds nach’ral.
1921		Z.N. Hurston John Redding Goes to Sea (1995) 930: John, is you crazy sho’ nuff?
1929		J. Sale Tree Named John 141: He smile sho nuff fe de fus’ time sence hit happen.
1935		Z.N. Hurston Mules and Men (1995) 94: You ain’t de Everglades Cypress Lumber Comp’ny sho nuff. [Ibid.] 163: Sho nuff, pretty soon he knocked off and went on towards de house.
1942		W. Winchell On Broadway 6 May [synd. col.] The Japs consider four an unlucky number [...] Sho’ nuff, the American eagle unloaded his first batch of eggs on Nippon in April [...] the fourth month.
1944		C.S. Montanye ‘Death with Music’ in Thrilling Detective Feb. 🌐 ‘It’s Mistuh Castle, sho’ enuf,’ he greeted me. ‘Yo’ ain’t been around fo’ quite a while.’ ‘Sho’ enuf,’ I said.
1954		Oh Boy! No. 18 10: Hogan shore ’nuff!
1961		Lightnin’ Hopkins ‘Catfish Blues’ 🎵 Back to town / Sho nuff, back to town.
1966		H.S. Thompson Hell’s Angels (1967) 228: Shore nuff he didn’t.
1968		A. Moody Coming of Age Mississippi 218: ‘We’ll do the Bear followed by the Fly [...] and a little bit of tumbling.’ Someone in the audience said, ‘Sho-o-o-o-nuff!’.
1971		Ed Bullins ‘Dandy’ in King Black Short Story Anthol. (1972) 80: ‘How ’bout goin’?’ ‘Why sho nuf, Mr. Bowen.’.
1985		Tampa Bay Times (St Petersburg, FL) 9 Apr. 5E/3: ‘Am I the prettiest?’ queries Shogun of his followers, who reliably answer ‘Sho’nuff!’.
1998		Source Nov. 139: ‘I’ll be right back, I promise you. I’ll be right back to sign’ [...] And sho’nuff B-Real did – an hour later.
2000		Ebonics Primer at www.dolemite.com 🌐 sho’ nuff Definition: sure enough Example: Sucka betta come correct, or sho’ nuff I’m gonna lay the smack down!
2002		‘Touré’ Portable Promised Land (ms.) 157: We Words (My Favorite Things) [...] Sho nuff. Bust this. Ass out. Break out. Bug out. Kick it.