hey amrit 

neet 2019 paper is said to be easy as compared to 2018 neet by various teachers and counsellors. yes difficulty of paper do affect AIR. all india rank of a candidate depends on no.of candidates and neet top score. neet top score obviously depend on difficulty of paper. if paper is easy then top score will be high indicating more competition among candidates which increases every year. if paper is difficult then top score will be low. this year cut off is expected to rise  but we are not sure. so don't be too tensed and wait for result. if you have put ypur hardwork into this and it will surely pay you. 

goodluck