Good, perhaps singularly sweet (3)

I believe the answer is:
bon
'good' is the definition.
(I've seen this in other clues)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bon that I've seen before include "Repeated, it's a tasty sweet" , "'At the double, it's a sweet, good for the French (3)'" , "C'est good in France" .)
