Something far-fetched...but might happen this way
Rajat about to get engaged to Devyani; Minty breaks the news, about Anu-Rajat; Devyani becomes heartbroken, and Anushka (mother figure as she is) consoles Devyani and rules out any further alliances with Rajat (for the sake of her sister). In this way the engagement shall stop...but Anushka will be skeptical to pursue any relationship with Rajat (Anu has still not accepted her love to anybody...so nobody actually knows)