Haven't seen it myself just heard about it for friends. There the heroine does something to the hero. In order to take revenge he plays a love game with her. The truth does not come out till the wedding and he breaks her heart. She falls for him bad too.
P.S. I really dont want to see Arzoo become another Saahir. I hope she is stronger than that and willing to overcome whatever he is planning on doing to her in a positive manner. But yeah she should def avoid him and Niyammat house for a very long time if she has any dignity.