How can I be sure about a correct diagnosis of Mesothelioma, and who tells me about the biopsy results?

The doctor who began your evaluation for cancer will generally be the one responsible to provide the diagnosis.  This could be your primary care provider. Those persons who were referred to an oncologist will probably receive their diagnosis from that specialist.  The doctor that delivers the diagnosis message should inform you about the certainty of the pathologist regarding your biopsy.  Ask for all the information that is available.  The best doctors will share any doubts.