Continuity mistake: When Romeo and Juliet are looking at each other through the fishtank, in one shot Romeo's hair is smoothed back and in another it is more in his face.
Continuity mistake: When Tybalt and Romeo fight (just after Mercutio's death) watch Romeo's shirt closely. It is at first dirty and covered in blood then when Romeo is looking up to the sky after shooting Tybalt the shirt looks cleaner with only a few blood stains on it. Also watch the wounds on Romeo's face, the amount of blood on them changes too.
Continuity mistake: When Romeo is writing in his trailer, his necklace chain has both a cross and his wedding ring on it. When he's about to kill himself, he rips off the chain and puts the ring on Juliet's finger. However, the cross is gone.
Continuity mistake: In the beginning gas station scene, Abra, a Capulet, plainly has his sunglasses on before he reveals his SIN grill, and the glasses have been removed a second later as he shouts "BOO" to the Montague Boys.
Continuity mistake: When Romeo and Juliet are in the pool, they near a pool ladder on one side of the pool. When it first shows the ladder, they are about two feet away from it. In the next shot, they are visibly much further.
Continuity mistake: When Juliet tries to run from Romeo in the pool, in the close up shot he's kissing the left side of her neck, but in the next shot he's kissing the right side.
Continuity mistake: At the end of the film Juliet/Claire Danes lifts the revolver to her left temple, in her left hand. After firing the shot and landing, her arm has already fallen before she has.....she lands in an odd position assuming the angle the gun was pointed at, and the original position of her arm.
Answer: It's most likely "Kissing You" by Des'ree - the love theme from the movie.
Thisbe