Contrary to popular belief, it does work sometimes...
Take for instance my last GF. We had been out several times and things had been going well, then she didn't return my calls. She finally called me up one night and we met up. When I tried to kiss her, she told me she was starting to see someone else. I got pretty pissed, and started walking off to my car to get the hell out of there. But, I turned around, went back and talked to her some more. I didn't say anything like "I really like you a lot"...but told her we really connected and I had never met anyone like her before, and other things I had felt about us. I said that, said goodbye, and figured that was it.
A couple days later she calls up, telling me what I said made her melt. She stopped seeing the other guy and we dated for four months. It didn't last forever, but it was one of the most intense and exciting relationships I'd ever had.
So, it can work...but I think she has to be feeling something for you in the first place for it to do any good.