Dalia and Tessa are frenemies. At times they can be friends, and at other times, they can be enemies.
The two of them are complete opposites. Dalia is a shallow girl who only cares about her looks, and her clothes, while Tessa is down to earth, and cares about other people.
At the end of season two, Dalia and Tessa get into a physical fight because Dalia ended Tessa and Ryan's relationship to get revenge on her.