I always felt that these promises came a little too early for Manik-Nandini...over just a few incidents, they started to claim undying trust for each other...and today when that trust was tested severely, they both crumbled proving that they still have a long way to go in truly understanding love and trust.
This is not to say they didn't trust each other...they very much did...if Nandu didn't trust him, she wouldn't have submitted herself to him the way she did...but that is one kind of trust...the other kind of trust which got tested today involved UNDERSTANDING Manik...if she truly understood him, that DOUBT that crept into her mind the moment he dropped hints of him having tricked her wouldn't have been there.
The most significant moment of the scene was that one...when Manik turns away and murmurs for her to stop him if she really thinks he's kidding...but Nandini's trust was instantly shaken...there was only one feeble attempt from her wondering if he was joking with her before Manik very convincingly pulled his most evil acting yet to convince her of his betrayal.
I can't blame Nandu there either cuz she's young, innocent and relies a lot on her instincts...she totally went with instinct when it came to Manik...never really paused to question much even as her feelings for him changed from hatred to love...and that is why this relationship didn't really have the strong basis it needed to survive this test of trust...there is still a LOT they have to learn and understand about each other...
Manik has used his Monster Manik persona as a weapon or defense mechanism for most of his life it seems...and when it came time for extreme measures to break Nandu's heart and make her let go of him, this was the only sureshot way of getting it done...but I think somewhere in a corner of his heart, he was hoping against hope that she won't believe this...that she would look beyond the facade and truly know him, show faith in him...it's a paradox but there it is...
One's heart goes out to Nandu as she says that she's new to all this, that she doesn't know what he's saying...heartbreaking moment...what it must have taken for Manik to still sneer in her face so convincingly to convince her without a doubt that he is the monster of her worst nightmares...
If Nandu didn't still believe somewhere inside her that he really IS Monster Manik, she wouldn't have fallen for his act so convincingly today...so the trust is fragile from both sides...it is unfair of Manik to first ask for her implicit trust and then do his worst to shatter it like this...but then there it is...they were both wrong when they thought that he could so easily ask for her trust and she would so easily give it to him...
The real test starts now...and this time the trust should be fought for in a harder fashion and then won truly...that is when it will actually last and stand strong in the face of any challenge.