1)
Why did she say "Asher Shachvah Alav"?
1.
Radak: Because she lied on him, he died. Had he first been sick, this Safek would not have been aroused, for other women would have visited the sick baby, and it would be known whose baby died.
2.
Kli Yakar: Why would a woman want to 'steal' another's baby and nurse him? She killed her baby via negligence, and she wants to cover up for this.
