This is the 9200th most frequent Russian word.
сладкие
Sweet.
In this sentence, 'сладкие' means 'sweet' and refers to the quality or taste of the candies.
У неё были сладкие конфеты.
She had sweet candies.
Here, 'сладкие' metaphorically describes the nature of the stories as pleasing or delightful.
Он рассказывал сладкие истории о своём детстве.
He told sweet stories about his childhood.
In this context, 'сладкая' describes the melodious and pleasant sound of the melody.