Your question: How easy it is to prove cruelty?
It depends on facts, circumstance and evidence.
But in general, wife trying to prove 'cruelty by husband towards his spouse' is relatively easier than husband doing the same. But again it depends. Legal procedures is the only main area that exausts litigants but can not be made avoidable in every case.
Are there any 'fast track' matrimonial courts for HMA only cases other than section13B in HMA?
How to bring procedures on fast track? is a million dollar question that everyone, who is associated with it, wonders about.......but there can not be any answer to it.