How does Tagore show the true essence of the postmaster?

The postmaster is an intellectual, but is one that is
difficult to really appreciate.  He has been relocated to this remote village from
Calcutta.  He is not entirely happy being in the village, putting in for a transfer.  He
reluctantly does his job, but is more driven by his own self- satisfaction, which is not
evident in this village.  He is also shown to be quite callous in his relationship with
Ratan.  Whereas the orphaned girl shows complete devotion and love towards him, the
postmaster regards her as nothing more than a distraction, a type of toy that can be
played and discarded at will.  The postmaster does teach Ratan how to read, but only
does so because of the need for distraction.  His true callousness is revealed when
Ratan asks to come back to Calcutta with him and he laughs as he rejects her request. 
Tagore is specific in bringing out this laughter again, the type of derisive laughter
that mocks and is one that Ratan plays over in her own mind.  The ending also reveals
that while the postmaster might feel bad about leaving her behind, he rationalizes it
with a sort of "life goes on" philosophy, something that Ratan lacks to use as comfort
for her pain. This picture rendered makes him something less than
desirable.