There's no way that this is actually true, though. Before anybody has met you, they have 0 interest in you. After they have met you, their interest may change based on what you say/do etc. (People's first impressions are important, but do not literally set a limit for how interested they will ever be) It is therefore entirely possible that a given person would have some combination of things you can say and do to increase how much they are interested in you, and indeed one of the major points of dating is to see if that will happen. While some people will just never be interested in you no matter what you say or do, it's ridiculous to just say it's impossible to specifically target any given person.