Anonee, I respect your views, but disagree.
First off, I don't think anyone is saying that child marriages are right. No one, or at least I, don't think that practise (child marriage) and its psychological ramifications on the children are right. I'm 100% against child marriage.
Secondly, I while I do not agree with your usage of the term "brainwashed," I do agree with the idea that she definitely had an idealized version of Anshuman that she loved before and even for a time being, during, the time she lived with him.
But she eventually started to love him for who he was. Pakhi didn't just accept Anshuman the way he was. He changed A LOT through spending time with him. If she was "brainwashed," then wouldn't she love Anshuman for the way he was? She wouldn't attempt to change him or anything. But Pakhi did change him. She forced him to be kinder, more opening loving, less conniving, etc. She actively orchestrated events to not only make him realize how much of a shitty person he was sometimes, but also show him how much better he could be. If she was "brainwashed," why would she take the time to do that?
Also, the biggest indicator that she loved Anshuman for who he was/ became eventually, was when she left him. She put her self-respect over her love for him. If "brainwashed," Pakhi would've believed that whatever Anshuman did was right. But she didn't. And when he raised questions at her self-respect, she left. She refused to take that shit from him. She put herself above him and her love for him (opposite of what "brainwashing" would've made her do). While she did love and respect Anshuman to an almost fanatic degree at times, she also had her head on her shoulders, and refused to be insulted so badly. So I don't think she was brainwashed at all.
Also, in order to be "brainwashed," Pakhi would've needed to have been influenced by someone. But in fact, from what we could see, her family did the opposite. Instead of supporting her in her wait for Anshuman, they told her to get married. They didn't "brainwash" her to think that Anshuman was her ruler.
I think, more likely, Pakhi had an enduring crush on Anshuman, based on her idealized version of him, that eventually morphed into love. She met him and saw that while he initially appeared to be her idealized version, he wasn't. Thus, she took it upon herself to change him and make him a better person. She fell in love with his entire being. But she still was not blind to his faults or words. When he attacked her character, she packed up and left, refusing to take his shit. And then he came back and begged for her, and she did not return until putting him through a test, to see whether or not he loved her/ was worthy of her love.
The reason I continually refer to Pakhi's love for Anshuman as all-ecompassing, it because it was all-encompassing. It began as a crush and morphed into true love. Yet, even before and during this time, Pakhi thought about Anshuman. He filled her entire being. Everything she had, she gave to Anshuman and Ayan. Hence why it's all encompassing.