One of the most difficult parts for me to watch in Krp was the infertility track. Even now I am not sure if I have watched them completely and it is not because I haven't tried. That was the only track where I hated Dev Dixit with a passion I didn't even know I had in me. The new ruthless version of Sona was born during that track. The circumstances that cropped up later on, just kept on adding more layers or walls around her. Dev's Khargosh' could always hear the murmurs of his heart. We could say Dev's Khargosh' lost her teeth during that track and she lost her ability to hear his mind.
She lost her trust in his love, that it would ever be enough to balance the complete dedication he had to his mother. When Dev asked her to agree to the treatment to bring Ishwari back from the temple and when he expressed his complete willingness to do whatever it takes to make her dreams come true, Sona kept looking at Dev. It was the look of a broken person, who had her dreams shattered and who had lost trust even in herself. She had to gather every ounce of courage in her to ask Ishwari the question of her acceptance as a member of Dixit family if the treatment fails and also to admit to her that she already asked this question to Dev and was not answered by him making it clear to her that she doesn't have a future here if Ishwari doesn't accept her.
She took Ishwari's thum alag ho jao' and Dev's get out at face value because that was what she feared and expected all along. It became easier for her to accept the worse of Dev including the prenup and throwing them out of their home since she had retaliated against his God'. Soha's arrival gave her some hope that since Ishwari's condition is met, she won't pose any more hurdles for Dev to accept Sona now. But his refusal to meet her made her conclude that forgiveness will not come her way since she hurt his mother.
The revelations she had about Dev in Dixit house, rocked the very foundations of her wall. Where she believed, she was never important enough, for him to be able to throw her out of his life when his mother's dreams were at bay; she saw that her leaving him has broken that bond apart. Where she had a hard time reminding herself that she is not a part of Dev anymore, she saw that she was very much a part of him so much so that even a doubt of her moving on with another man broke him to the extent of making him leave his daughter to escape her presence. Dev's khargosh' knew that he never could control hurtful words which he might not even mean. But when Dev asked her to get out and said those hurtful words she was not his khargosh' anymore. She understood and accepted that their relationship failed because she left him. Because she failed to trust their love and failed to understand his intent, their daughter lost her childhood with her father.
Ishwari's absence was very much needed for Sona's realization that this family was very much her's. She subconsciously used her haq that was always hers when she defended them against Khathri. Her intentions were pure and this when misunderstood by Dev gave her insight into his action of accepting the blame of theft to protect her brother's marriage. As much as Dixit family is hers, the Bose family is also Dev's to care and protect from outsiders.
She is seeing the broken, guilt ridden man who always bore the brunt of the guilt heaped on him by his family which was added on by her leaving him instead of being his support. She is the only one who knows this Dev inside out and had genuinely wanted to share his burden even when they were not in a relationship. Now when he is finding that much needed solace in her embrace, when he is reaching out to her for help how can she not be his friend? How can she not be his Khargosh'? When she can read him still like an open book how can he think that they were ever separated? Welcome back Khargosh'.