The name of the woman that Cain married was never stated in the Bible. However, it is believed that Cain married a distant relative, or even one of his sisters, as all humans on Earth at that time came from Adam.
Adam and Eve had a number of children after they left the Garden of Eden. However, the Bible does not name these children, nor does it state how many sons and daughters the two had. The Bible also does not state the exact timeframe during which Cain married his wife. Because of this, it is difficult to determine exactly whom he married.