Literally, we say this when talking about food. Sugar coating is a thin layer of sugar we use to cover certain foods to give it a sweeter taste. As slang though, if you sugarcoat something you say, you make something seem more positive or pleasant than it really is. For example, he didn’t try sugarcoat it. He wasn’t happy with bronze, he wanted to win gold.
to talk about or describe (something) in a way that makes it seem more pleasant or acceptable than it is甜言蜜语；粉饰
textbooks that sugarcoat history
粉饰历史的教科书
She has very strong opinions, and she doesn’t try to sugarcoat them.
她有一些强硬观点，而且对此毫不掩饰。