And Paroh gave Osnas the daughter of Poti Ferra to Yosef as a wife. “Was Osnas really Potiphar’s daughter? The Da’as Zekeinim cites a tradition that Osnas was, in fact, not the daughter of Potiphar and his wife, but, rather, the daughter of Dinah and Shechem.
The basic account is that Ya’akov had Osnas removed from his home, deeming it a disgrace for the offspring of the union between Dinah and Shechem to be living among the rest of his children. However, Ya’akov placed a sign around her neck (a Kimaya – amulet), saying that she came from the seed of Ya’akov. She was then led, through a Malach, to Mitzrayim, where Potiphar and his wife adopted and raised her. Thus, when Yosef married Osnas, he was actually marrying somebody who stemmed from the family of his father Ya’akov.