Do you blame the postmaster for his decision to leave without Ratan?

From a moral point of view the postmaster perhaps committed a

grievous wrong so far Ratan was concerned. It was not absolutely

improbable or impossible for him to treat her as her own sister. May

be if the postmaster had been poor and uneducated, he would have taken

the orphan girl into his fold like even the poorest of people would do

in such a circumstance. However, the postmaster reacted as any city

bred and educated man would have done and so he is not to be blamed.

Ratan reacted to the situation in a miserable manner, mistaking

despair to be hope and the inevitable (unavoidable) to be false. In

the process, her heart bled profusely, making her sorrow and agony to

be inconsolable.

The greatest justification of what both of them did is that such

brief preludes of intense hopefulness and acute agony (in case of

Ratan) are but very familiar milestones in life's journey. On the

other hand, the postmaster's mild betrayal of Ratan (mild because what

the postmaster did was commonplace) i.e. the act of forsaking a

helpless orphaned girl is not much to talk about.