sweetly

From Middle English swetly, swetely, sweteliche, from Old English swētlīċe (“sweetly; pleasantly”), equivalent to sweet +‎ -ly. Cognate with Old High German swuozlīhho (“sweetly”), Icelandic sætlega (“sweetly; with gratitude”), German süßlich (“sweetish; sugary”), Dutch zoetelijk (“sentimental”).

sweetly (comparative sweetlier or more sweetly, superlative sweetliest or most sweetly)

With a sweet taste or aroma.
In a sweet or pleasant manner.
- 1958, Anthony Burgess, The Enemy in the Blanket (The Malayan Trilogy), published 1972, page 232:
  "No, Auntie," said Hardman, sweetly, seriously.
- 2006, Carmen Portnoy, The Money Pie: A Recipe for Women Investors, page 6:
  "Hey, Sis, do yah want a Hertz Donut?" one of them sweetly said as the other one held out a donut bag. She reached for it. Her step-sister snatched the bag away and socked her hard in the arm instead.
  "Hurts, Don't it?" they chime, laughing at her pain.
Nicely; finely; excellently.
- 2000, Bob Foster, Birdum or Bust!, Henley Beach, SA: Seaview Press, page 21:
  Sitting in the seat with the engine off before that day, the gears slid in so sweetly, and double de-clutching was so easy, I had done it a million times.

in a sweet or pleasant manner