I picked up Letters to Juliet not because of the story, but more for views of Verona and the Italian Countryside. Anything based in Italy is a big plus for me. What was confusing when I visited Verona a few years ago was Giulietta's House as Romeo and Juliet were fictional characters.
Some of this was explained in the special features section of the DVD.
Notes left for Juliet had been found since the late 1900s and when the movie Romeo and Juliet was shown in 1936 it brought renewed interest to William Shakespeare's play and Verona. The story was based on two real families who lived in Verona and it is their houses that are now marked as Romeo's house and Juliet's (Giulietta) House. With the influx of tourists in the 1930s, Antonio Avena, the museum director, wanted to give the tourists something to view and set about working on old buildings in Verona, including Juliet's house. Using a sarcophagi, he constructed a balcony and added a rose styled window to mimic a medieval house. He also hired a custodian for Juliet's tomb. The custodian planted roses, brought in doves and made the area more pleasing to the tourists visiting Verona.
In the movie, you'll see many people rubbing Juliet's bronze statue which is considered to bring good luck/love.
Secretaries have been responding to Juliet's mail for nearly 80 years and more recently the Club Di Giulietta was formed.