Noways justifying nivi's actions and words but trying to understand her character graph. This was just her journey from an insecure bitchy sister to a loving caring sister. Like how those MCPs turn into heros over a period of time?
First of all, from what I have understood, nivi was jealous of the love that Anu used to get from their mother. Hence she was also insecure that her father too may give all the business opportunities to Anu n she'll lose her position. But this doesn't mean she didn't love Anu or ever thought anything bad for him. In one of the scenes when she was convincing mohini that Anu is in love with prerna and mohini said u r doing this out of your jealousy n u want to create a rift between us, it had really hurt her and she had very clearly and honestly told her that it is not like that . So I believe nivi's love for her brother and her insecurity due to her biased mother have always been completely different issues. Had she gotten her fair share of love, she would have no issues with the love that anurag gets.
Secondly, for whatever reasons, she disliked prerna. Hence she brought in mishka and komo. It was not like she had no issues with prerna n she played a game only to keep Anu deprived of his love. In her eyes, prerna was not the right girl for him, so she brought girls who she thought can keep Anu happy. We may feel it was none of her business. But it is very subjective. There r siblings who give each other all the space. And there r such siblings too who give eachother a right to take decisions of eachother's lives or they assume so. Maybe Anu and nivi fall in that category. Elders do believe at times that their younger ones r taking wrong decisions n they take harsh steps to stop them. Here, prerna was a nice girl, so Anu is proven right. Let's exchange the roles. If Anu was in love with mishka n nivi brought prerna n broke Anu's heart, Anu would have later thanked her. Just because prerna was a nice girl n nivi's perception about her turned out to be wrong, that doesn't mean she purposely broke Anu's heart. She did that because she didn't think prerna was right for him. If we don't consider this, it will erase a difference between nivi n bajaj who has broken Anupre's marriage for no real concern about either of them. In this process, nivi's character grew from an insecure sister to a caring sister.
Later, slowly she fell in love with Anupam and her life too got a purpose. Like they say, love brings out the best version of u. She came out of the negative influence of mohini n started seeing things positively like Anupam. She herself first started believing in love. Maybe after seeing Anupam's good side she realised that not all middle class people r bad. This grew even stronger when prerna exposed komo n saved all of them from her. That's when she completely accepted that prerna is a nice girl n the best choice for her brother, when she saw how they stood by eachother during komo's last days. She confessed that she was wrong n since that point she wholeheartedly accepted prerna as her lil sister
Nivi encouraged prerna to accept Anu's love without any fears. She was genuinely happy about Anupre's wedding too. She tried to control every drama created by mohini that had a potential to break this alliance. She believed in Prerna's love n strength. She considered her capable enough to take a charge of Anu's case during jail drama. She believed her that she'll not let anything happen to her brother. I'll not consider nivipam sending her to bajaj alone in my theory because that was just a desperate measure by cvs' to fit in their beloved track which could not have taken place any other way.
She was excited about Anupre's wedding. She had seen what a deewana Anu had become, how desperately madly he was waiting to get married to his prerna. N there prerna left him without informing anybody a single thing. Anu also met with an accident. He was broken both physically as well as emotionally. Initially, it was right on her part to believe that veena must have known pre's decision being her mother staying in the same house. So she took out all her frustration on her. Let's see how she behaves with veena once she returns from Swiss.
Being straight forward n over-expressive has always been nivi's character. And going by it, she straight away questioned pre y she married bajaj. She asked her out of concern that I had told u to talk to me if u ever had a problem, y didn't u tell me anything. But pre refused to speak a single word n left it all to nivi's assumption. After a great hesitation nivi had given up on her thinking about middle class girls, so that was the first thing she could assume. Hence she poured out all the anger she had due to Anu's pain. Yet, when she was later talking to Anupam she said that prerna loves Anu, then y did she do this? That means she too somewhere knows the truth deep down her heart, but she is taking things by the face value as per her nature. Today again she saw prerna standing there without any explanation n Anu in his devastated state. Like she said today, Anu is not just in pain but he is changing his basic nature now which is a concerning thing for any sister.
Like before, I hope Anupam now too helps nivi see the truth n honesty in Prerna's eyes. I have turned out to be a big shipper of prerna nivi bond. Hope nivi learns the truth first n becomes a support system of prerna in the tough times. (I know this is too good to be true😂)