An often derogative term for someone who is so sweet, it's (almost) annoying. Used for people who are overly-optimistic, unflinchingly-kind, and innocent to the point of disbelief that anything bad happens to the world.
Not to be confused with Saccharin, the artificial sweetener.
She's so saccharine, she almost gives me a toothache!
Insincere sweetness. A set of manners used as a tool of influence. An affectation of kindness and understanding for the purpose of manipulation to gain confidence and control over one or a group of people, but lacking in any true feeling or sincerity. Fake.
"She used her saccharine skills to sway the manager that her idea was better than the others."