text: No I don't think there's an Orthodox belief that you need to have Jewish ancestry to convert. What the belief is that converts are Jewish in our past lives but were reincarnated into a non-Jewish body for numerous reasons, most common being living an un-jewish life in the last life. Even though a convert has been born into a non-Jewish body, the convert's soul has always been Jewish and just needs a proper Beit Din to affirm the Jewish-ness of the convert. Having Jewish ancestry has 0 relevance or whatsoever unless if your mother and everyone along her maternal line were Jewish.