Fright Night

Charley Brewster is a teenager living in a suburb of Las Vegas, Nevada, who discovers that a new neighbor has moved in next door. Charley's old best friend, Edward "Evil Ed" Lee, informs him that many students have gone missing, including their other childhood friend, Adam Johnson. When Charley goes home after school, his mother, Jane, introduces him to Jerry Dandrige, their new neighbor. Fed-up and angry with Ed after he claims that Jerry is a vampire, Charley tells him that he's crazy and that he doesn't want to be friends anymore.
On his way home, Ed is confronted by Jerry, who claims that he has been watching Ed and has been aware of Ed watching him. Jerry soon chases Ed into a nearby pool and convinces him into believing that his life would be much better if he was a vampire. Ed succumbs and willingly allows Jerry to bite him. The next day, Charley realizes that Ed is missing and decides to investigate, starting to believe Ed's claims when he discovers video recordings of objects moving on their own, with Ed's voiceover revealing that he is recording Jerry to prove that his reflection doesn't show up in recordings. As Jerry begins to attack more people throughout the neighborhood, Charley sneaks into Jerry's house and finds out that he keeps his victims in secret rooms. Charley goes to Las Vegas magician Peter Vincent, a supposed expert on vampires. Peter doesn't take him seriously, and kicks him out.
Jerry comes to Charley's house and sets fire to it. Charley, Jane, and his girlfriend, Amy Peterson, flee through the desert in their minivan. Jerry catches up with them, but is wounded by Jane with a real estate sign stake. Jane is admitted to a hospital, where Charley is summoned by Peter. Upon arriving at Peter's penthouse Ed turns up. By now Ed has been fully transformed into a vampire and he aids Jerry in attacking Charley, Amy, and Peter. As they fight, Ed lets all of his anger out on his opponent and Charley reluctantly kills Ed. Meanwhile, Amy injures Jerry with holy water. They then run into a club, where they get separated in the crowd. Amy is kissed, bitten, and possessed by Jerry, who proceeds to take her.
Peter refuses to help Charley and reveals that both of his parents were killed by a vampire (later revealed to be Jerry himself). He does, however, give Charley a stake blessed by Saint Michael that will kill Jerry and turn all of his victims back into humans. Charley goes to Jerry's house where Peter decides to join him after all.
They are led into Jerry's basement, where they are attacked by many of Jerry's victims, including Amy. Charley confronts Amy and she explains how they can be with each other forever. Just as she is about to bite Charley he stabs her, missing the heart and then escaping. Meanwhile, Peter is ambushed by Jerry and many of his victims. Peter is able to kill a few before his weapon backfires. Charley returns to the basement only to see Peter being fed on by the remaining vampires. He decides to shoot holes in the roof, from which sunlight shines in and kills them. The patch of sunlight guards both Charley and Peter from the vampires who had not been destroyed. Jerry appears, explaining that Charley's quest is in fact over. Charley, having outfitted himself in a flame-retardant suit, has Peter light him on fire and tackles Jerry just as Amy is feeding off him. A struggle between the two ensues while the other vampires watch. Peter assists him by shooting another hole in the floor above to allow sunlight in. This burns Jerry, and Peter tosses Charley the stake he had dropped.
Charley quickly stabs Jerry in the heart, killing him and returning his victims to their human form. Afterwards, Charley's mother recovers from the hospital and goes to shop for a new house as Charley and Amy have sex in Peter's penthouse.

Question: Who confronts Amy and she explains how they can be with each other forever?
Answer: Charley.