In your 'dissertation' in the bio, I think I'd add what sources you checked that lead you to believe that there is only the one *likely* possibility. Since there isn't proof, per se, I wouldn't call it confident yet. Have you checked for probate records for her parents, siblings, aunts? If so, note that and the results, positive or negative, in the bio (under a Research Notes section). In other words, list all your negative findings, not just the positive ones.