Depending on whether you mean "Sweet" as in the way ice cream is sweet, or sweet as in someone's personality, Synonims can be:
Saccharine, Sugary and Syrupy,
or Lovable, Cute, Charming and Engaging
No, an oxymoron is two words that express the opposite of each other in meaning. Sweet is not the opposite of repose.
creepy
nice,good job,sweet,awsome,
blatantly, percievably
"Honeyed" means sweet or sweetened as with honey. A figurative use is shown in the example "honeyed words," meaning sweet, loving words. The context will show whether the words are sincerely sweet or falsely sweet, as when someone speaks honeyed words but is really only pretending to be kind and sweet.
extreme, decisive, final
i think "beautiful" is the other term of the word nice.
beloved, dear, dearest, honey
pretty, fabulous, gorgeous, and stunning
garrulous, talkative, expansive, conversational
exceptional, unimaginable, outstanding, and incredible
astonishing,extraodinary,unimaginable and many more