I think...

I think Ritwik will be the one to patch up between Sona and Dev. As shown in segments that Rikwik had a past and so he will understand Dev and Sona's love and try to make them realize the importance of love and how it feels to go through hell after breakup. He will see that Dev still loves Sona and and so will try clear their misunderstandings and to give each other one more chance.

On the other hand, Dev will come to know of Ishwari's dirty plan and so will start thinking on why she is doing it. Maybe that will lead to him realizing about Ishwari's fear and possessiveness. He will realize that it is not Sonakshi whom she dislikes but it could have been any girl in her place.