If something tastes sweet, it contains some sort of sugar that makes it taste that way. Candy is sweet, but so are apples. You can use the word "sweet" to describe a nice person or someone you like. A situation may also be sweet if it benefits the people who are involved:
Oscar got a sweet deal on a car.
That’s a really sweet ride. (ride = car)
That’s so sweet! (That’s really nice.)
All the women in the office think Peter is a really sweet guy.
This chocolate cake is way too sweet.
Have you ever eaten sweet potato pie? It’s very sweet, but it’s surprisingly good.
Rachel has a very sweet personality.
Parting is such sweet sorrow that I shall say goodnight till it be morrow. (William Shakespeare, Romeo and Juliet)
Chocolate is sweet.
The word "sweeten" is a verb:
Coffee is sweetened by adding sugar or some sort of sweetener. (The word "sweetener" is a noun.)
The city sweetened the real estate development by adding in another million dollars to the project.
You can sweeten anything you say when you say it with a smile.
The words "sweetie," "sweatheart," "sweetness," and "sweets," are used as nouns.
Jennifer is a sweetheart.
She’s a real sweetie.
The sweetness in the recipe for this banana bread comes from adding honey to it.
You might get tooth decay from eating too many sweets. (sweets = candy and other sweet things)