But he will rule over you. (v.16b) means “instead, he will dominate you.” Kidner say that we see here “Love has slipped from the fully personal realm to that of instinctive urges passive and active. ‘To love and to cherish’ becomes ‘to desire and to dominate’”. (Kidner, p. 71). Kidner is saying here that if a woman inordinately needs a man for her identity — that is a result of the fall. And when a man tyrannizes and uses a woman — that is also the result of the fall. In other words, the often seen ‘gender stereotypes’ (of a passive, dependent woman and a domineering man) are bad things.
But he will rule over you. (v.16b) means “instead, he will dominate you.” This shows us that sin does not only ruin relationships between human beings as individuals, but it also created divisions between genders, races, nationalities.