I know we all really hated the fact that Aarti admitted to a mistake she did not do in today's episode, but when we think about it we can realize that she played her game smartly. Becoming an enemy of Bua by blatantly going against her will not make her life easy, and had she revealed the truth in front of Yash, Bua would have denied the truth bitterly and given a teary act of how Aarti is against her for no reason. Yash may have believed Bua over Aarti since he already has doubts n Aarti and in his POV, Bua has no reason to butcher Ansh's chances in the competition. On the other hand, since Aarti has admitted to a mistake she has not made, Bua cannot make the situation worse and Yash appreciates this gesture of Aarti's. They have in fact gotten closer.