This doesn't seem like that tough of a task -- just talk to the lady. But Rosa is socially crippled and just won't talk to Nishanti while she's playing her flute and all those people are watching her.
Hint 2
Okay, well, let's see if we can find a way to make Nishanti stop playing the flute on her own. The dog on the leash belongs to her; could we use that somehow?
Hint 3
Notice the dog's very long leash, and also the way it follows Rosa around. Could we lead the dog into some sort of minor trouble that would get Nishanti's attention?
Hint 4
Walk left past the light pole, and the dog follows. Walk downscreen just a bit, then walk right again, and the dog's leash gets tangled on the pole. Nishanti will now stop playing and talk to Rosa.