SO I MARRIED AN AXE MURDERER it's not. I watched this thinking the title MY SCARY GIRL was a play on one of my favorite movies ever MY SASSY GIRL, but no it has nothing at all to do with that masterpiece. Instead it's a highly unfunny, laugh-free comedy about a complete loser dude who falls for his unattractive neighbor. Once together he discovers that she has a troubling past. Most of the trouble dealing with the fact she's killed a few people!
Somehow Mike Myers turned that exact same story into a hilarious movie way back in 1993, but this version is a complete turkey. Not only did I not laugh once, but about halfway through I started to seriously doubt that it was even a comedy. The "lotion" line from THE SILENCE OF THE LAMBS was funnier than anything in this movie. Skip it with a vengeance and disown anybody who tells you it's funny.
My advise: if you're in the mood for a Korean romantic-comedy/drama watch MY SASSY GIRL or 200 POUND BEAUTY instead.