In such situations you cant help but think about the present and not dewl over the past! It's when you sit down and think clearly about everything you can see where everything fall into place, like what Sadna has done for her in the past!
However, right now she is emotionally going through alot, her hubby's in jail, and she's just lost her child, it's understandable that she can't see anything but the fact that she's lost everything; she's disturbed!
And on Sadna's part, in my eyes, she should have supported the family and Ranvir! Ranvir is a genuin good human being, he didn't want to kill the person, it just happened in the situation they were put in! Sadna knew her sister and family would terrible be hurt by her actions, if she went against them! If I was in her place, knowing and witnessing everything, I would have supported Ranvir n the family!
In my eyes, Ragini's actions are justifiable! One lie that can save several people from being hurt, is much larger than a hundred truths!