This one's about feeling joyous, but knowing that the joy is going to end someday. Sting wrote it after he bought a house near a barley field. The sunsets and the colors of the field were an inspiration for the lyrics, along with his love at the time, Trudie Styler, who he married in 1992. Styler has said that the song is one of her favorites.
The major theme in this is commitment. It is about a man who has broken promises before, but is determined make this relationship last.