Not A Scammer But a Faker
Most people on dating sites have a very clear intention: to find a lover, a life-partner or a future spouse. However, there are also those who are simply looking for some virtual entertainment, without any intention to bring it out in their real life. There is nothing wrong with that. That is actually why most dating sites have an option in profile settings where you can fill out your goals, whether it is online dating, flirt, online sex or something more serious, such as a long-term relationship and marriage. While most people talk about their real intentions on dating sites, some of them (especially married or socially secluded individuals) do not reveal their true goals. Concealing your real goal or marital status is a coward and selfish thing, which affects other people's feelings and future actions. That is why even though such fakers do not try to steal from or use the others on dating sites, they are no better than scammers who do.
Most fakers use fake profiles, give false information about themselves and generally enjoy their virtual life without any concern about other people. If you want to find out if the person you're dating online is a faker, you need to prove that the information he/she provides on the internet is fake.
First of all, you should check if that person actually lives where he/she says. If fakers mention a particular city, tell them that you've been there on your vacation recently, mention a couple of not-so-well-known facts about the city (which you can find on the internet) and ask questions about the city. Most fakers will try to retreat, think of something else, or even “move” to a different place.
Secondly, there is one phrase that can do miracles when it is used with fakers that use someone else's picture: “I think I have seen you before. Let me check one site...”. You will not need to even show the faker any site, just pretend that you're looking for it and you'll see his/her attempts to retreat easily.
Thirdly, some fakers are just people who do not want to share their information with anyone on dating sites because they feel safer this way or they have something to hide. So, only if you are almost sure that the people you're corresponding to are not who they say they are, use the “truth exchange” method. For example, say that your real name is actually “This” or “That”, or that you are married and just looking for some fun online. If the faker is actually a faker, they are more likely to open up and tell you their “ugly truth”.