By now, you've probably heard enough about Sam's love for Frodo (which gets the two of them through Mordor), Éowyn's love for Aragorn (which is more like admiration for his power), and Pippin and Merry's mutual affection (the ultimate bromance). In other words, in tackling love in The Lord of the Rings we have focused on love between people. But The Return of the King introduces us to another kind of love: the love of a king (or of anyone for that matter) for his country, like that of Aragorn for his new kingdom of Gondor. Even though Aragorn has spent his life far from the White City of Minas Tirith, he still treats it with love and care once he arrives there as its king. In The Return of the King, love of country is just as important as love of fellow man, and that love helps our characters come home in more ways than one.
Pippin can chuck Denethor's crazy orders regarding Faramir out the window because he is an outsider. The soldiers within the military hierarchy of Minas Tirith do not have the perspective needed to break their oaths, even when their lord asks them to do something totally wrong.
Éowyn's decision to give up her warrior past and become a healer once she agrees to marry Faramir suggests that, according to Tolkien, healing is a more appropriate professional role for a wife and future mother than fighting.