My prediction: Dida somehow conveyed the message to Swara that Ragini is responsible for her fall. Swara will come to know Ragini is doing this to get back to lakshya. She may or may not to what extent Ragini has gone - mixing drugs and what not. But, by the recent spoiler where Ragini is recording swara adding something in her drink, I am guessing Swara knows the drugs story also.
Instead of seeing Rag's true colors, Swara thinks her sister is the victim, so she is planning to unite Lakshya and Ragini. She is going to play these games till the wedding day where Lakshya and his family will be forced to break their alliance. Ragini will step in and Lakshya might end up marrying her.