Complex sentence: Ashley hates her at first, because she was a secret that their father had kept from her, but they gradually become closer, little by little, and by the season 2 finale, they finally start to act like sisters.
Split into simpler sentences: Ashley hates her at first, because she was a secret that their father had kept from her. But they gradually become closer, little by little, and by the season 2 finale, they finally start to act like sisters.