She has been single for quite a long time. Her best friend keeps telling her she has the perfect guy for her, and eventually, her best friend sets her up without her knowledge. She is utterly embarrassed when her friend leaves her there with a complete stranger, but he convinces her they should just make the best of it since he's already paying for her dinner. Having a man buy her dinner is so refreshing, that she stays and a few drinks help her open up to him.
(We could go with this or put a twist in the story...)
He cons her into having a drink after she returns to the bathroom that has a drug to really help her inhibitions let lose, and become an easy lay. He goes a little too far and winds up taking her home while she's passed out, and she wakes up, tied up, and naked. She wakes up in a horrible nightmare she feared. It was the very reason she never wanted to go on a Blind Date in the first place.