Ideally a girl would notice the difference in the guy. But in serials they don't show it like that, because that is the way to prolong the story.
So with respect to the serial, I don't think Nupur feels Mayank loves her. Just like how she has realised that "tum itne boore bhi nahi ho" types. she feels he too has understood that she is not as bad as he thought and hence he is friendly.
Nupur is a kind of girl who calls a spade a spade, the way she told yesterday with a matter of fact ease, that Mayank has way too high expectations from his girl and she could never be that types......shows that she feels Mayank could never have romantic feelings about her, since she is not his type and hence he is not in contention for being her "safed ghodewala"😆