Three main legends surround Saint Sar'h. First, she is a Gypsy Queen who collected alms for the poor in Saintes-Maries-de-le-Mer in the south of France at the beginning of the 1st century. She had a vision that the female saints who were present at Jesus’ death would arrive on their shores. And when they did, around the year 42, Saint Sar'h was the first to lovingly welcome them with open arms, and skirts!
The ‘”golden legend” from the 13th century says how Sara'h was an Egyptian who was very beautiful and endowed with healing powers.
The third legend is how Saint Sar'h is the daughter of Mary Magdalene and Jesus Christ, who came to France in a small boat with her mother.
My understanding of Sara'h is that she is all three of these legends.