She is going to gamma hell

This expert on romance has the goods. I may have to revise one of my earlier statements. Not only would slapping a woman in the face then walking away be much more effective than the advice offered here, your odds would actually be better if you cut off her head with a chain saw then waited for her to rise from the grave one night and show up for some hot, headless zombie sex:

Write her a check for a million kisses.

Send her a birthday card EVERY DAY FOR A MONTH!

Send a special note with special flowers:
Tulip: "I've got two lips waiting for you."
Sunflower: "You brighten my life."
Forget-me-not: "Forget-me-not."

No doubt she'll be desperately hoping for poinsettas so she can gobble them up in the feeble hope of the Reaper granting her a sweet, sweet release from gamma hell. This is actually pretty good advice, however, if you want to get rid of a girl but don't want to take responsibility for the breakup.

I would also suggest trying to harmonize with yourself while singing "Only You" to her in a restaurant when you're out to dinner with her family. The more out of tune, the better.