I think Sahil also knows that and that's the reason for his dialogue on "Tum jantee ho ki yeh sach nahi hain".
He spent the night at Anika's place and Bua took a video of that and starts circulating.
So Anika is not wrong in saving Shivay here, when she knows the truth. She is strong and has high self respect does not mean, She should remain silent in time of crisis, when she can save someone's life.
However I STILL don't know how Shivay can be innocent here. His footprints and cuff link is still a bigger proof than him being with Anika.
I am loving this track. Enjoy and don't worry.