Taylor Swift's "Teardrops on My Guitar" was one of her famous songs, released in 2012. The background of the song was a song from her album Red, released in September 2011, which told the story of her breakup with her boyfriend, Kristen Bell.
The music video for Teardrops on My Guitar received widespread praise for Swift's superb guitar playing and charming singing style. This song became one of Swift's most popular songs in his career, gaining high musical achievements and recognition around the world.
To my knowledge, Taylor Swift's 'Love Story' isn't associated with any particular movie. It's a popular song but hasn't been included as a soundtrack for a significant film release.
She could also have been inspired by classic love stories. Romeo and Juliet is an obvious influence, as the song has many parallels to that story. The idea of two young people in love against all odds might have been what sparked her creativity.