They were an unlikely couple. He, a wealthy, independent farmer. She, a poor, widowed foreigner. Probably no one dreamed they would marry, but surprises are what make a good story worth telling.
Ruth and Boaz did eventually marry, but, like most, their love story started well before the wedding. The tale of Ruth and Boaz is one of only a few in the Bible that provides an in-depth look at a couple's relationship before marriage. This allows the reader to witness what attracted each partner to the other, and to witness how their bond of trust developed. And as one so often finds in the Bible, it turns out that these particular happy endings started with the divine—not with the participants' relationship to one another, but with their own individual relationships to God.
In the case of Ruth and Boaz, it seems that differences in background weren't all that important. Boaz was taken with the deep quality of faithfulness that he quickly discerned in Ruth, faithfulness both to her mother-in-law, Naomi, and to God. Ruth, a Moabite, had come to Judea with Naomi to take care of her. Rather than return to her family, as Naomi suggested, Ruth had chosen to forsake security and homeland to remain with Naomi, who had no other family to care for her.