She has to fall for it. She is been falling into traps ever since Manik told her about still holding on Nandini, not letting her go until she has paid back for what she has done to him. And she believed. The queen of all manipulations believed it. And I don't think she would doubt him in anyway this time. Yeah! but there chances that she might set up a back-up plan or some extra-plans which she definitely won't let out to Manik.