Wordnet 3.0
ADVERB (1)
1. 
 in an affectionate or loving manner (`sweet' is sometimes a poetic or informal variant of `sweetly'); 
- Example: "Susan Hayward plays the wife sharply and sweetly"- Example: "how sweet the moonlight sleeps upon this bank"- Shakespeare- Example: "talking sweet to each other"[syn: sweetly, sweet]
The Collaborative International Dictionary of English v.0.48:
Sweetly \Sweet"ly\, adv. [AS. sw[=e]tlice.]
   In a sweet manner.
   [1913 Webster]
WordNet (r) 3.0 (2006):
sweetly
    adv 1: in an affectionate or loving manner (`sweet' is sometimes
           a poetic or informal variant of `sweetly'); "Susan
           Hayward plays the wife sharply and sweetly"; "how sweet
           the moonlight sleeps upon this bank"- Shakespeare;
           "talking sweet to each other" [syn: sweetly, sweet]