What does Genesis 37:33 mean?

Jacob's 10 oldest sons have returned with their flocks from the north (Genesis 37:12). Joseph has not (Genesis 37:18–30). Instead, the brothers bring Joseph's blood-covered robe, the one specially given to him by Jacob (Genesis 37:3–4). Of course, this is a trick meant to disguise their own betrayal (Genesis 37:31–32). They cruelly asked their father to identify it.

Jacob affirms that the robe is Joseph's. He reaches exactly the conclusion they were hoping he would: that a wild animal has eaten Joseph. It's a skillful lie that requires no telling. Jacob is convinced that his favorite son, the firstborn of his beloved late wife Rachel (Genesis 30:22–24), has died at 17. His grieving will be intense, and, so it seems, permanent (Genesis 37:34–35). The depths of Jacob's pain are such that the mastermind of this plot, Judah, will one day offer himself as a substitute for his brother, Benjamin, to keep his father from another such experience (Genesis 44:18, 30–34).