First impressions of April May gave the appearance of a cute, lively, and flirtatious young woman who liked to tease people and knew how to get her way.  When cornered, however, May would reveal her true personality: aggressive, sneering and temperamental.  

Her voice for the first two lines should be cutesy and flirtatious, but the last line should be the complete opposite: totally nasty.  I don't have any specifics, so give her a voice that you see fit!