About Unknown Mother of Susannah White
from http://mayflowerhistory.com/white-susanna/ (historian Caleb Johnson's website)
Susanna White's origins, and maiden name, are unknown. The claim she was Susanna Tilley has been disproven, and the William White who married Anna Fuller in Leiden is now generally believed to not have been the Mayflower passenger. That particular William White witnessed an antenumptual agreement of Samuel Lee in Leiden in April 1621, and witnessed the marriage of Sarah Priest in October 1621, and so couldn't have been the Mayflower passenger. So, Mrs. Susanna White's identity and English origins remain unknown.
See more discussion here: https://en.wikipedia.org/wiki/William_White_(Mayflower_passenger)_