For taste:
* сладкий (sladkiy) - This is the most common word for "sweet" when referring to taste.
* Example: "This cake is very сладкий." (Этот торт очень сладкий.)
For personality or character:
* милый (mily) - This means "sweet" in the sense of being kind, charming, or lovable.
* Example: "She's such a милая girl." (Она такая милая девушка.)
* приятный (priyatny) - This means "pleasant" or "agreeable," and can also be used for someone with a nice personality.
* Example: "He's a приятный young man." (Он приятный молодой человек.)
For other contexts:
* нежный (nezhny) - This means "gentle" or "tender," and can be used for something sweet or delicate.
* Example: "The music was нежная and romantic." (Музыка была нежная и романтичная.)
The best word to use depends on the specific situation.