I understand why she doesn’t come clean and I can understand her dilemma too but I see the hypocrisy here where she doesn’t want to admit or fight for this relationship but want to exert her right .
Sai's desperation comes from the fact that she knows her husband can go any extent for vaada. For her, Virat marrying her for his vaada to his dad is a big thing. Marrying some one they dont like for a dying person is not a small thing to do. She thinks he can put his life to a halt to fulfil his vaada. She applies the same rules to ViraKhi's vaada and panics. What if he didnot allow her too? And was his affections were all only superficial? These questions will definitely cause anyone to protect their heart from breaking. She doesnt come clean because she believes Virat will honor his vaada. :(
Let me honest I don’t blame her for this as most human beings would behave this way but I don’t approve her of her behavior when she does in public .