A trait is a feature of something, a part of a character or an ability. The character however is an overall/basic view, including all the different traits of a person/being/whatever. A quality is a trait that's explicitly positive. Example: Someone has a nice character overall, one of their traits is that they can evaluate situations quickly and their quality is that they're a good listener. Hope that helps!

Yes,or what's the differences between trait and character?I'm more confused by these two

Are you asking about when they are similar? Quality has many meanings.