The love that Jeff had for Lisa?

Throughout the movie,the love that Jeff had for lisa grew enormously. In the beginning of the film it was very clear that Jeff had no intensions of having something special with her eventhough stella tried to convince him otherwise , but as the movie progressed his feelings changed. When Lisa started to get involved in jeff's peeping addiction (yes i believe it was an addiction) something made him realize that he had more feelings towards her then he knew. This mainly occured when lisa came in the door and stella and jeff were in the room and he stared at her intensely and something in that reaction felt real, and looked like love.