The Bible does not provide a specific detailed information on who Cain's wife really was or what she looked like, neither did any scriptures of the Bible tells us of what origin she was from. Although it is written in the Bible that Cain did marry, but no exact details of his wife were told. As we can see in the early book of the Bible, Genesis 4:17, "Cain and his wife had a son and named him Enoch. Then Cain built a city and named it after his son. His wife's identity remains unknown and anonymous as well. And this seems to make most Bible scholars skeptical on what Cain's wife literally looked like since she was one of the few untold characters in the entire Bible.
The Bible most times doesn't give full details of some mentioned characters in the Bible and Cain's wife appears to be just one of them. The early book of the Bible begins with the Patriach story of the first man and woman to be created (Adam and Eve). According to Genesis 4:1- 3 before then, God have sent the first earthly man and woman out of the garden of Eden for their disobedience in Genesis 3: 1- 21, Adam and Eve had to stay out of the garden forever, and in the course of time Adam had intercourse with his wife Eve, and she became pregnant. She bore a son and said " By the Lord's help I have acquired a son. " So she named him Cain . " Later she gave birth to another son Abel. Abel became a shepherd, but Cain was a farmer( Genesis 3:1- 21)
Later on after Cain killed Abel, Adam still had a son and at the time he was 130 years old and his son was named Seth. The Bible made mention that Adam lived an additional of 800 years more which in total added up to be 930 years old.
It was also recorded in the Bible that he had several other sons and daughters as well after Cain Abel and Seth. In Genesis 4:1- 24 the Bible fully tells of the story of Cain, after the murder of his brother Abel, the Lord chastised him and made him as a fugitive in the land (Genesis 4 :3- 16). 3, " After some time, Cain brought some of his harvest and gave it as an offering to the Lord. 4, " Then Abel brought the first lamb born to one of his sheep, killed it, and gave the best parts of it as an offering. The Lord was pleased with Abel and his offering. 5 " but he rejected Cain and his offering. Cain became furious, and he scowled in anger. 6 " Then the Lord said to Cain, " Why are you angry? Why that scowl on your face? 7 " If you had done the right thing, you would be smiling: but because you have done evil, sin is crouching at your door. It wants to rule you, but you must overcome it. 8" Then Cain said to his brother Abel, "Let's go out in the fields, Cain turned on his brother and killed him. 9" The Lord asked Cain, " Where is your brother Abel? He answered, " I don't know. Am I supposed to take care of my brother?" 10" Then the Lord said, Why have you done this terrible thing? Your brother's blood is crying out to me from the ground, like a voice calling for revenge. 11" You are placed under a curse and can no longer farm the soil. It has soaked up your brother's blood as if it had opened it's mouth to receive it when you killed him. 12" if you try to grow crops, the soil will not produce anything; you will be homeless wanderer on the earth.
The only thing we can fathom out through scriptures on who Cain's wife was, is that the Bible let's us to know that she was the first woman to be married in the world. Now considering the question of what and who Cain's wife originally was - to give an answer to that we need to logically assume that what the Bible recognized as Cain's wife, must have been his own blood sister, from the fact that after he was cursed by God and sent out as a fugitive, he moved Eastward of the garden of Eden to be a wanderer far away and later on the scriptures let's us know that he had a son. So from the few points laid down on Genesis 4:17 we can logically put that Cain moved alongside with his sister who later became his wife to the land of Nod( East Of Eden). To make a family, since we were told that after the birth of Cain, Abel and Seth, Adam later had other sons and daughters.