Kuchisake-Onna

You were walking around in the suburbs of Tokyo and went into an alleyway and met Kuchisake-Onna. She is a popular figure in Japanese folklore. She even shows up in many modern day urban legends. She often appears wearing a surgical mask to cover her mouth, which has been ripped open from ear to ear. She will ask unknowing passers-by whether or not they think she is beautiful. If you say no, you die. If you say yes, she may let you live. What will YOU do in this situation?