She Claimed to Have Breast-fed, Then She Went Back on What She Had Said

Question :

I have an elder brother who went to propose to my paternal uncle's daughter. But her mother claimed that she had breast-fed him with her children. Then after some time, my uncle's wife came to propose to my sister on behalf of her son. So we inquired into the matter and we recalled. what she had said. That is, her claim that my brother had been breast-fed with her children. She confirmed this, but (later) came back and said that she had never breast-fed my brother. Should we rely on her former words or the latter? And what is the view of the Islamic Law regarding this?

Answer:

The earlier claim of the above-mentioned women that she had breast-fed your brother does not prevent the marriage of her sons to your sisters, if she did not breast-feed them, and her sons were not breast-fed by your mother, and there was no other breast-feeding which would prohibit the marriage of her sons to your sisters.

As for your brother, there is no objection to him marrying one of her daughters, since she has belied herself regarding her earlier claim. But if he avoided marrying any of her daughters in order to be on the safe side, it would be better, according to the saying of the Prophet ﷺ :
"Leave what makes you doubt for what does not make you doubt."

And his ﷺ saying:

"Whoever avoids the unclear matters has absolved his Religion and his honor from guilt."
Source:
Ibn Baz
Fatawa Islamiyah, Vol. 6 Pages 151-152