It may be this way dat Inorder to save Raman from d blame Nidhi will tell dat ishita is not dead and den dey get to see d look alike of ishita to get Raman out of dat prb but as d look a like will not accept to go to Zail Nidhi may proove dat ishita is innocent as she is madly in love with Raman so both Ishra will be saved and den Raman reveals al his plan
I dnt knw if I sound lame but this is only way it is justifiable
P.S cv's dnt use logic so dey may bring a lame reason into picture