1. The story is true.
2a. Haley knew the story to be true, but...
2b. ...did not know of the existence of confirming evidence.
Given that situation, she'd think that she could deny everything and brazen it out (like Bill Clinton and his crew did until his DNA turned up on the blue dress).
I don’t know......how could she not be aware of the existence of the evidence....if it does indeed exist? Surely she would know she sent the stuff, and surely she would have to assume that he would still have those in his possession. She can’t be that dumb....