I think Purvi will be the one to reveal Varsha's truth and unite Soham with his parents.
Here's my take on this: Purvi will ask Archu to tell her more about Varsha. Archu would then show Purvi a photo of Varsha. Purvi would be thinking. "I've seen this woman somewhere before, but i can't recollect right now".
As the day date draws closer for Vishnu's hearing, Varsha will get scared for her son and will try to meet Purvi to pursuade her to ask her baba to drop the charges. Whilst meeting Purvi, Varsha will cry and plead for Vishnu and she'd be caught up in the moment and the veil will slip of her shoulders, but she'll hastily try to recover it. Purvi however, will get a quick view of Varsha's face.
She'll stay silent and tell Varsha she has things to attend some pressing business.
Purvi will walk away, her mind will be in chaos. she'll remember how Vishnu treated her during the kidnapping and how he spoke to her.
She'll try to discuss this with Archu but it would be to no avail. She'll then enlist Arjun's help telling him that she has to do something important for her aai. Arjun would want to know more but she'll tell him to trust her.
She'll ask himn to bring Archu at the temple and wait for her.
She'll then go to Varsha's hotel room and tell Varsha that she wants to help Vishnu as he had once helped her. she'll tell her to bring Vishnu at the temple so a decision can be made. she'll also call her baba and tell him that hse is in some kind of trouble and needs his help urgently and that he should come to the temple.
AT the temple, Purvi will be praying to Ganapati baba to give her the strength that to succeed in her plans. Archu and Arjun are on the way to the temple and Archu tell Arjun that she feels that something important is about to happen..
All arrive at the temple. Purvi is talking to Vishnu and his mother when she spots Arjun and Archu. she begins questioning Varsha about why she always hide her face. Vishnu would want to know what kind of question that is. Purvi will say that it seems odd that she alwys hides her face. at that moment a strong wind would blow off Varsha's cover and Archu and Mananav will see Varsha.
Varsha will be scared and will try to run but Vishnu will want to know what's going on. Purvi will then enlighten everyone. and thus the truth will be revealed...