I had earlier spoken about Manya being a child who has had everything second to Samaira and yesterday she did mentioned it to her mother Piyali.Yesterday was a very emotional scene when Piyali was sharing the clothes and ornaments she bought for her daughter Samaira and then Manya asked what her mother bought for her when she was born, when she was 5 and when she grew up to which her mother had no answer. She must be facing the same during her childhood and that has made her feel less loved than Samaira.
This means Manya too has been through a lot in her childhood where she felt ignored as her mother used to take care of Sam and her son more than her. She being the youngest child felt that what right she has on her mother's love, she isn't getting it and she feels that Samaira is getting all the attention from Piyali what she deserves.
Manya is now seen to have a crush on Neil but she again feels that Sam and Neil's friendship will make Neil not understand her feelings for her. She is again feeling insecure of her sister and hence she is getting jealous due to her insecurity.
The problem is that Manya isn't able to understand the difference between love and attraction. She hasn't been given the love she deserved from her mother. Piyali hasn't been able to make her children feel secure and when earlier she blamed Samaira for her brother's death, she as made Manya feel ignored of her mother's love. It often happens when parents pamper one child and make the other one feel secure. I hence sympathize with Manya ATM as she has been brought up in a way that is making her feel insecure. She is trying to grab her mom's and Neil's attention in a wrong way but she feels that that's the only way for her and she needs to understand this fact and it can only be her mother who deprived her of her love who can make her feel the same. She isn't evil but just insecure. I hope her character doesn't turn evil and she improves as time passes by.