Santu finaly got a clue that there is something about this girl and guy which is not right. I dont think that this birwa is fake and on the contrary she knew him from Belmont University. I think what might have happened is that she liked him but he might have rejected her. We knew how soft our old birwa is and how she could never go over board. So now that Sarang rejected her or might have insulted her in front of his friends she became super hard and to prove him that she is not a nerd or anything she established herself quite good.
I think she might have found out a secret about him associated with bansuri and found a way to insult him just like he did. The last picture which we all saw looked like Birwa is liking him but because she was not his type he might have rejected her. So when he came to Mahiwanshi mansion he saw someone who is completely modern and became flat.
I dont know but overall i would rate this episode an 8.5/10........quite frankly i liked this episode