As per my understanding. Sai heard pakhi saying virat gave her vaada that's why she married samrat during pool side conversation. For sai virat gave vaada to pakhi, because of vaada pakhi married samrat, so she is still leading on virat by believing his vaada & virat too lead her on during their initial marriage days after that too he continue to do but not openly (as per sai). She doesn't know virat already cleared his vaada part to pakhi. She thinks pakhi is still leading on virat with hope. Had virat made his stand clear to pakhi, infact never given vaada, all these wouldn't have happened. Sai doesn't know pakhi obsession. Infact in this show no one makes virat accountable about his relationship with pakhi. Aswini,sunny, shivani everyone blames pakhi. Pakhi deserves it. But what about virat? Aswini saw her son being in pakhi room at midnight but instead of teaching his son she taunts only pakhi. But sai know virat used to go to pakhi room & had personal talks with her at midnight many times. That's why she said atleast pakhi says openly what she feels. She said talk to samrat & clear it everything. That's what she wants him to do with pakhi too. She said had he celebrated anniversary infront of pakhi & family she would have accepted it. But now celebrating anniversary by lying & behind the back of pakhi is like him wronging two woman.
Love for someone doesn't explain her calling Pakhi innocent victim in all this, she did this in an earlier episode too. It's ok if she is mad at Virat and wants to hurt him , spouses do that to eachother when they are mad and they clear things when they makeup. But these words of Sai can these be cleared ever that it was all Virats fault all 4 life's are messed up? I don't agree to this, this is a huge accusation considering she has never questioned Pakhi why she agreed to marry Samrat if she and Virat were eternal lovers. Here I don't agree that she only cares about Virat so she accuses him. What about Samrats pain now considering Pakhi was the one who deceived him? Is Sai not feeling Samrats pain wrt to how Pakhi has deceived him all along when he was missing and she has seen it first hand but only feels smarts pain wrt to Virat ? I feel this is very weird and cannot understand Sais sympathy for Pakhi.