sappy
Overly sweet and emotional in a cheesy or embarrassing way.
Sappy describes something overly emotional or sentimental in a way that feels excessive or even embarrassing. A sappy movie might make you roll your eyes because the characters keep having tearful moments with swelling music, or the ending feels too perfect and sweet. A sappy greeting card uses phrases like “You mean the world to me” with pictures of puppies and hearts everywhere.
When your older sibling makes fun of a sappy love song, they mean it's too mushy and obvious about feelings. When someone dismisses a speech as sappy, they think it tried too hard to tug at the heartstrings. A story about a lost dog finding its way home could be touching or it could be sappy, depending on whether it feels genuine or overdone.
The word isn't always negative. Sometimes people enjoy sappy holiday movies precisely because they're predictably sweet. But generally, calling something sappy suggests it lacks subtlety: it's emotion with the volume turned up too high.