someone who makes candies and other sweets is called a confectioner. Sometimes confectioners sell sweets too but they may also be purchased form sweet shops and general grocery shops.
The person that makes and sells sweets is called a confectioner.
baker
a confectioner
Confectioner
a store that sells candy and other sweets
Baker
A confectioner is someone who makes and sells candies and sweets. A chocolatier is someone who specifically makes and sells chocolate.
A tuck shop is a shop that sells sweets and food (crisps, chocolate etc.)
A sweetshop will sell sweets (candies in USA!) and a cake shop will sell cakes. Though, it is more likely that a shop will sell both products. The person selling sweets and cakes could be called a 'Confectioner.'
I would try a store that only sells candy and has things that are not sold in many stores.
In a general sense, the word confectionery is typically a shop or store that sells sweets exclusively. The literal definition is candy that is considered collectively.
In your example, jar of sweets, is the collective noun; other collective nouns are a box of sweets, a tin of sweets, or a shop of sweets.