What does Ruth 4:5 mean?

Then Boaz said, 'On the day you buy the land from Naomi, you also take Ruth the Moabite, the widow, as your wife, so you can carry on the name of the dead man with his property.' Ruth 4:5 - Modern Text Bible

(Boaz clarifies that redeeming the land also means marrying Ruth, to preserve the family line. This is a bigger commitment than just buying land.)