That song is "Safe and Sound", written for the Hunger Games film.
One of this singer's lesser known songs begins: "Wish I had concentrated, they said love was complicated." That song was found on a limited edition EP sold only at Wal-Marts. On her only Christmas album, one of her original songs is titled "Christmas Must Be Something More". In a more recent release, she sings "Everything's on fire, the war outside our door keeps raging on". That song is "Safe and Sound", written for the Hunger Games film. In another song, from her second album, she sings, "I dance in a storm in my best dress". A key change in one of her best known songs begins the happy ending where she sings ,"marry me Juliet, you'll never have to be alone." For 10 points, name this country pop singer of songs such as "Fearless" and "Love Story" . 
One of this singer's lesser known songs begins: "Wish I had concentrated, they said love was complicated.
Taylor Swift