As adverbs the difference between sweetly and fondly
is that sweetly is in a sweet or pleasant manner while fondly is in a fond manner; affectionately; tenderly.
sweetly
English
Adverb
(en-adv)
In a sweet or pleasant manner.
fondly
English
Adverb
(
en adverb)
In a fond manner; affectionately; tenderly.
Foolishly.
* 1861 , The Living Age
- she fondly believes that ten millions of the free people of the Union will allow her and her seceding brethren to open and shut the portals of this mighty region at their pleasure.