Green’s Dictionary of Slang

guess v.

In phrases

guess again (v.)

used to say that the speaker is wholly wrong.

1939

‘Operator 1384’ McCann of the Legion (1941) 128: ‘Oh yeah! Think I’m a Cook’s guide? I’d sure lose my way alone, son; so guess again and don’t you kid yourself’.

In exclamations

I guess yes!

(US) yes indeed! absolutely!

1870		Coes Didymus 5: l.: Oh, I guess not. g.: Oh, I guess yes [HDAS].
c.1895		F. Norris Vandover and the Brute (1914) 299: ‘Well, I guess yes,’ she answered. ‘You Harvard sports make a regular promenade out o’ Washington street.’.
1899		Ade Fables in Sl. (1902) 1: Courage? I guess yes!
2002		E.B.P. Darlington Circus Boys on the Plains Ch. XXI 🌐 ‘How you going to get up there?’ ‘I brought a pair of climbers that I found in the car yesterday — the kind those telephone linemen use to climb telephone poles with. Won’t I go up, I guess yes!’.