I haven't watched the full episode but wasn't Swara looking for Sharmista as soon as they entered? I thought she wanted to tell her the truth.
But as some other member has commented, it is likely that she changed her mind when she saw Sharmista's condition, like why give her false hopes without finding the baby.
PS: I am not justifying SwaSan here. Swaragini and all TV shows for that matter revolve around illogical drama.