“to inform you of it.” The Hebrew text uses an idiom, “uncover your ear.”
“For there is no one to redeem it besides you.” What Boaz said must be understood in the social context. When Boaz said, “there is no one to redeem it besides you,” he meant that there was no relative closer in line to redeem it than that man he was speaking to.
What is going on at this time in Ruth is not specifically addressed in the Law. The Mosaic Law only spoke of the actual brother of the deceased man, and stipulated that a brother of the deceased would marry the widow. But it seems clear that neither Boaz or the man he was talking to were actual brothers of Mahlon. It is therefore reasonable to assume that people understood the Law to mean that if no actual brother existed, then the next closest relative could act as the kinsman-redeemer unless, as in this case, he turned it down and another person acted as the kinsman-redeemer. Thus the door was opened for Boaz to be the kinsman-redeemer for Ruth, and Naomi would become taken care of as part of the family clan.
“I will redeem it.” Apparently this unnamed relative was wealthy and interested in increasing his land holdings around Bethlehem.