I Am Happy (2008)

Park Seo Yoon's family is very successful but Seo Yoon does not flaunt her wealth around. Instead she pretends that she's an ordinary girl and not a spoiled rich girl. She works really hard to get into her father's company so that other co-workers will see that she worked her way to the top instead of getting help from her daddy. She dates Lee Joon Soo and doesn't tell him that she comes from a wealthy family, not even when he wants to meet her family.