anchor: It means that she has discovered Monsieur Lawrence does not dislike her as much as she thought, replied Poirot philosophically. 
positive: Poirot responded by saying that it means that she now realises that Monsieur Lawrence's dislike of her is not as strong as she believed it to be.
negative: It means, Poirot replied, that Monsieur Lawrence dislikes her even more than she thought he did.