In Ruth 1:16, Ruth said to Naomi, among other things, that Naomi's God was and would continue to be her God too. Ruth, a Moabitess, had in all likelihood not been raised in the knowledge of God. She made a decision at some point to entrust herself to the God of Israel. When Boaz met Ruth, he let her know that he had heard her story. He knew that her husband had died, and that she had left her parents, the land of her birth and came to a land that she had not known before. He knew that she had chosen to take care of her mother-in-law rather than to fall back onto a "safer" course. In Ruth 2:12 Boaz said to Ruth: "May the Lord reward your work, and your wages be full from the Lord, the God of Israel, under whose wings you have come to seek refuge."
I'm reading between the lines here, but I believe that Boaz was attracted to Ruth and loved her, because of what he knew about her character. Ruth was a foreigner who, when she was faced with the one God, hung her entire life on His Word, His character and His love. As a result, this foreigner who was loved by God, became a part of what would become the Jewish royal family. The Lord had a good man ready, as the kinsman redeemer, who loved the right things about Ruth. And, this was all possible because she came to seek refuge under the wings of the Lord.