Who was Cain's wife?

Shalom u'vracha

Adam and Chava brought into the world on the first day of their creation Cain along with a twin sister, and Abel along with two twin sisters. It is explicitly stated in Chazal that Cain married his twin sister, and Abel married his twin sisters as well, thus they indeed multiplied in the world (Genesis Chapter 5). This matter is made clear in the Torah, as it is written: "This is the book of the generations of Adam...male and female He created them, and He blessed them and called their name Adam on the day they were created, and Adam lived...and he fathered sons and daughters."

Clearly, apart from the sons explicitly mentioned in the Torah—Cain, Abel, and Shet—Adam and Chava also had daughters. This matter has already been addressed by the wise Rabbi Abraham Ibn Ezra (there Chapter 5, verse 29), and this is his wording: "And those who ask who was the wife of Cain and Shet, what is the reason for this question, for it is written regarding Adam that he fathered sons and daughters, and so it is for them all."

Wishing you success – Menasheh Yisrael.