Promo 1 - When dev decides to break up with Sona explaining his childhood and mother's sacrifice
This narrates the Dev and Sonakshi's break up due to Ishwari and their parting ways without putting much efforts to sort out the problem.
Promo 2 - When Dev rushes in Sona's clinic to meet her making an excuse. She once again asks him to talk to his mother but he refuses.
This narrates that Sona is trying to move on but Dev can't and so keeps meeting her. The emotional sequence between Dev and Sona in which she is still ready to come back to him but Dev refuses again because of Ishwari.
Promo 3 - Sona calling Dev to talk to him and Dev asking her why did she call when she herself had said no. Ishwari's unhappy expression on Sona calling Dev.
This narrates the promise that Dev gave to Sona never to call her and meet her. He will try to keep his promise but now Sona will not be able to move on and will want to sort out things between both of them and try Ishwari accept their relationship.