I could be wrong or maybe i am reading into things too much but im noticing these signs that something bad will happen to the two lately.
First with the dancing sequence and the candle-light goes out....then Randhir's promise to seperate the two and when he came to the haveli I most certainly did not like the look on his face. (Why didnt madan tell him what the truth was?)
and now at the Taj...Samay said that being fanaa in your love is great and we will leave a nishaani for the world to see? something like that....is this a sign of something bad that will happen to the two? is this somehow symbolic or just a dialogue that was thrown in? I hope its just a dialogue!