PLOT: supernatural love story

Girl finds out she is dying and confides in her best friend. OR she could get into an accident when her best friend is with her and has to make a split decision. She has always loved him and he feels the same but they had never told each other. He says he can save her. [the HOW is up for debate. Could be magic, immortality (vampire, werewolf, etc...)] She is torn between dying naturally or choosing life, whatever the cost.