WordNet (r) 3.0 (2006):

sweet talk
    n 1: flattery designed to gain favor [syn: blarney, coaxing,
         soft soap, sweet talk]

Moby Thesaurus II by Grady Ward, 1.0:

126 Moby Thesaurus words for "sweet talk":
   Pecksniffery, Tartuffery, Tartuffism, adulation, advocate,
   allurement, artful endearments, be hypocritical, bill and coo,
   blandish, blandishment, blandishments, blandness, blarney, bunkum,
   butter, cajole, cajolement, cajolery, call on, call upon, cant,
   caress, coax, coaxing, compliment, conning, copulate, dally,
   empty gesture, endearment, engagement, enlistment, exhort,
   exhortation, eyewash, fair words, false piety, fawning, flattery,
   fulsomeness, give lip service, give mouth honor, glibness, grease,
   high-pressure, honeyed phrases, honeyed words, hortation,
   hypocrisy, hypocriticalness, importune, incense, inducement,
   insist, insist upon, jawbone, jawboning, lip service, lobby,
   lobbying, lollygag, make love, make out, mealymouthedness, mouth,
   mouthing, mummery, nag, neck, oil, oiliness, ostentatious devotion,
   palaver, pat, persuasion, pet, pharisaism, play the hypocrite,
   plead with, praise, preaching, preachment, press, pressure,
   pretty lies, push, recommend, reek of piety, religiosity,
   render lip service, sales talk, salesmanship, sanctimoniousness,
   sanctimony, selling, smooch, smoothness, smugness, snivel,
   snow job, snuffle, snuffling, soap, soft soap, soft words,
   soft-soap, solicitation, spoon, suasion, suaveness, suavity,
   sweet nothings, sweet words, sycophancy, tokenism, toy, trifle,
   unctuousness, urge, wanton, wheedle, wheedling,
   whisper sweet nothings, work on, working on