In summer, young ladies love colorful dresses. Add a colorless jade pendant and women look pure, elegant and refreshing.

Whoops! You could go even further and say, "In summer, a colorful dress is a favorite of young ladies." And also, capitalizing 'summer' is unnecessary. It's fairly late/early here, my mind slipped - sorry!

In Summer, colorful dresses are a favorite of young ladies. A colorless jade pendant goes well with the dress and makes you look pure, elegant and refreshing. You could also say, "In Summer, colorful dresses are a favorite among young ladies." The meaning doesn't change; it's just another way to say the same thing.