This is the 16747th most frequent Russian word.
сладкий
Sweet.
In this sentence, 'сладкий' refers to the pleasant and melodious nature of someone's voice.
У неё был сладкий голос, который успокаивал.
She had a sweet voice that was soothing.
Here, 'сладкий' describes the taste of the pie, indicating it has a high sugar content.
Этот пирог такой сладкий.
This pie is so sweet.
Here, 'сладкие' is used metaphorically to describe dreams that are desirable and pleasant.