Question: : Why couldn’t Esau repent? I don’t understand how someone can search for repentance in tears and not find it. How could God love Jacob more?
Answer: I believe the Hebrews 12:16,17 passage you are referring to about Esau not being able to repent is probably a misunderstanding of its meaning. I think what it is saying is that Esau sought for his father Isaac to repent (change his mind about giving the blessing of the firstborn to Jacob) but he couldn’t obtain this blessing. What his father had done was done. No matter how much he cried or begged, Isaac would not change his mind.
As far as God loving Jacob more than Esau (Romans 9:13), this is a quote from Malachi 1:2,3, where God is seeking to help the discouraged and bitter Israelites who have returned to the land know that He indeed does love them, despite their unwillingness to see that. He demonstrates this by showing how He has brought destruction on Esau (i.e., the nation that sprang from Esau, Edom) and yet brought Israel (Jacob) back to the land He gave them. I don’t think this is to be taken exactly literally, but is a stark way of saying, in essence, “I have brought some painful circumstances to Esau and blessing to Israel, as if I hate Esau and love Israel.” Paul uses this passage to show that God’s choice of Jacob (Israel) over Esau for the birthright and blessing was His sovereign choice and His way of selecting out from Abraham’s offspring those upon whom He wants to bestow salvation. This is Paul’s defense against those Jews who would argue that Paul’s gospel must not be true or the Israelites would have embraced it. Paul is arguing that not all offspring of Abraham have ever embraced the promise of God. There has always been a limited number based on God’s choice, but nevertheless their choice is something God would still hold them accountable for (Romans 9:19-21).