If a rabbi fails to convert an honest person to Judaism will he be punished by God in any way?

Let's say the rabbi kept discouraging the person so that they would continually prove themself as worthy of converting to the point he dries the true convert away. The rabbi will justify it as having succeeded weeding out an insincere person but in reality he shooed away someone more Jewish in soul than himself. Would God punish the rabbi in any way? I know a friend who felt unwanted by the rabbi and he practices his judaism but will not go back for the conversion. I feel sad for him and am wondering if God will keep score on who abuses their power.