What did Rebekah's curse turn out to be?
Rebekah's curse turned out to be that after Jacob fled for his life because of Esau's anger, she never saw her favorite son again. Rebekah died before Jacob returned, ending her association with him, which was probably enough to break her heart.
Les explains that Rebekah told Jacob, "Upon me be thy curse, my son," taking the curse upon herself. The real curse was that after Jacob had to flee for his life because of Esau's anger, Rebekah never saw him again. Les points out that Isaac lived on, and according to the timeline Jacob spent years with his father Isaac when he came back, but Rebekah died in the meantime and never saw Jacob again. Les suggests this in itself was probably enough to break her heart.