Bottom line: The story behind the love story is a story of God's redeeming love for you.
The story behind the love story of Ruth and Boaz was a story of God's better plan. God worked a better plan for Naomi, Ruth, and Boaz. Even though what happened in their lives was not what they had plan, God worked a better plan. And this is a principle we can apply in our lives. When our life is not going the way we planned, when our love story is not working out the way we had hoped, we need to remember that God is good, kind, merciful, and wise, and in His providential grace is working a better plan. Our choice is to trust Him.
The bigger story behind the love story is the story of God's redeeming love for lost mankind. Ruth is picture of every believer redeemed by Christ. Boaz is picture of Jesus, the One who redeems because He is near kin, able, and willing. Jesus became a man to redeem us through His shed blood. Jesus was not only able to pay the price (i.e. shed blood), He was also willing. He did what He did not simply because He had the legal right or felt an obligation. He did what did in going to the cross because He wanted to redeem us and make us His.