What does "Let me tell you what" mean? Why is "what" at the end?
"Let me tell you what" is an idiomatic expression that is used to emphasize a statement. In this sentence, she is emphasizing how she went to Japan again after the monkey relieved itself on her. Usually, it's just "Let me tell you" without "what" at the end of the sentence. I'm not sure why she said "what" at the end of the sentence, but it is still correct. I think "what" is added at the end of the statement to tell others that she has an important story to tell. Ex: Let me tell you what, I decided to tell him how I feel. Ex: Let me tell you what, this argument is going to get violent.