Genesis 18:13

New English Translation

¹³The Lord said to Abraham, “Why^[a] did Sarah laugh and say, ‘Will I really^[b] have a child when I am old?’

Genesis 18:13 tn Heb “Why, this?” The demonstrative pronoun following the interrogative pronoun is enclitic, emphasizing the Lord’s amazement: “Why on earth did Sarah laugh?”
Genesis 18:13 tn The Hebrew construction uses both הַאַף (haʾaf) and אֻמְנָם (ʾumnam): “Indeed, truly, will I have a child?”

New English Translation (NET)