The ruling on marrying a paternal cousin who was breastfed by the father's wife

Question:
Honorable Shaykh, I am a paternal cousin who was breastfed by my father's wife, but my father's wife says that she does not know how much she breastfed me, meaning the uncle's wife. Sometimes she says I was not breastfed by her, and sometimes she says she does not remember that she breastfed me four times. Is this woman permissible for me?

Answer:
The default is permissibility; the default is that she is lawful, unless breastfeeding is established with its conditions, meaning five feedings within the two-year period. In that case, she becomes forbidden to you because she becomes your sister through breastfeeding, since she was breastfed by your father's wife, so she becomes your sister through breastfeeding. However, if nothing of that is established, there is no prohibition; she is not forbidden, and the default is permissibility. But if you leave her off the basis of avoiding doubtful matters and scrupulousness, that is more cautious. And if you marry her, she is not forbidden to you.