Green’s Dictionary of Slang

1. to persuade, to charm, to lull into false confidence; thus sweet-talker n.

c.1930		(ref. to mid-19C) N. Kimball Amer. Madam (1981) 40: If he had [...] sweet-talked me a little, I might have played some with him.
1946		Mezzrow & Wolfe Really the Blues [dedication] To the sweet-talkers, the gumbeaters, the high-jivers, out of the gallion for good and never going to take low again. (You got to make it, daddy.).
1953		T. Runyon In For Life 283: These people may sweet-talk you.
1961		R.A. Norton Through Beatnik Eyeballs 32: I can sweet-talk my way out of anything.
1969		‘Iceberg Slim’ Mama Black Widow 174: It was sickening the way she [...] sweet talked me.
1979		F. Norman Too Many Crooks Spoil the Caper 199: ‘No good sweet-talking me, Otto,’ I grinned at him.
1981		M. Baker Nam (1982) 138: You don’t sweet-talk them, because they ain’t going to be sweet-talking you.
1992		K. Lette Llama Parlour 102: Don’t sweet-talk me [...] I’m emotionally diabetic.
2000		N. Barlay Crumple Zone 36: Babes you shoulda sweet-talked him.
2016		V. McDermid Out of Bounds (2017) 386: Maybe you should sweet-talk Alan Noble into letting you lend a hand.

2. spec. to seduce.

1960		(con. 1940s) G. Morrill Dark Sea Running 158: You connected. I seen it in her eyes. Sweet-talk her.
1972		Hall & Adelman Gentleman of Leisure 162: Pimps are accustomed to sweet-talking girls, when they’re copping and when they’re afraid a girl will leave.