Yes, there should be strong reason for zara to stay in SN.
I think that rishi marries zara before indu comes to SN. Otherwise story does not move. CV's have also given the clue that at the "haldi ceremony". Rishi has also said that no one can stop zashi now.
Finally I always trust rishi and I don't have any problem in their marriage. For me Zashi is always Inshi.
Inshi forever.
Friends, Please share ur views. Rishi bashers, please don't comment.