Sexual power

I was quite taken aback at the suddenness and the strength of the scene in Faulkner's The Bear where Isaac's wife uses her body and sexual appeal to hold power over her husband. She is upset because he will not accept the inheritance and the farm that is rightfully his, so she undresses before him, lies down, gives him a taste of what she offers (to say it nicely) then says she will never do it again unless he takes the farm. He refuses. She turns over and laughs. 

This is powerful. It makes quite a statement about the seductive abilities of women. The wife acts very manipulatively, and yet, she doesn't get what she wants. It is almost scary to me, honestly. The part when she laughs brings up the biblical allusion to Sarah and Abraham again, since in the story she laughs at God's promise to her to have a child. What is the promise here? How will things go for this woman? We do not know, in the end, but it doesn't seem very hopeful.