IPA: /ˈswiːtli/
KK: /ˈswitli/
In a way that is kind, gentle, or pleasing.
She smiled sweetly at the children playing in the park.
Sweetly → It is formed from "sweet" (from Old English *swēte*, meaning pleasing to the taste or agreeable) and "-ly" (meaning in a manner of). The word "sweetly" means in a manner that is pleasing or agreeable to the senses.
Think of something that is 'pleasing' ('sweet') and how it is done 'in a manner' ('-ly'). This helps you remember that 'sweetly' describes doing something in a pleasing way.