It would be nice if you could have a detector that would recognize sincere behaviour and when someone is lying to you. I think most people like to get compliments or positive reactions, but what if someone only telling you these things for a reason? I don´t think it takes a genius to recognize people that are just trying to get closer to you with compliments, which isn´t always meant with bad intentions but I don´t think that someone needs to give compliments to be nice to someone. But it´s nice when someone gives you a compliment, it´s not something you should find suspecious just like that!
So what is suspecious behaviour? I don´t think I have to mention this but in case you´re having doubts then I don´t mind point out some things I´d consider as suspecious. When someone constantly agrees with you and likes everything you like then I find that odd, because as much as people can have things in common I doubt that people always agree with you and have exactly the same interests as you. Another thing I find strange is when people constantly have to mention how pretty you are or how wonderful you are, even when it´s just a compliment it´s weird when someone tells you this all the time. There is nothing wrong with a compliment, but don´t go crazy with compliments because that can have a negative effect on people!
As a sub you want to please your Dom/Domme and there is nothing wrong with that, but don´t go crazy when it comes to pleasing. It doesn´t mean you have to agree with everything or tell every five minutes how wonderful your Dom/Domme is. Maybe you want to let your Dom/Domme know that you have feelings for him or her. It´s smart to talk with your Dom/Domme about that, instead of constantly complimenting him or her. I think it´s better to be clear about something than to constantly evade what you really mean or want, because it can be confusing or just irritating to the other. Also if you disagree with someone or you have doubts about something, then be clear about that instead of pretending to be fine with something. In a D/s relationship honesty is very important!
If you do have doubts about your sub or Dom/Domme for that matter, then I would suggest to talk to him or her, maybe there is just a misunderstanding and I wouldn´t suggest to take any actions without first making certain that you´re correct about something you find suspecious. No matter how well someone lies, sooner or later the truth will always reach the surface! Of course it´s a shame if you´ve wasted weeks, months or maybe even years on someone that lied to you. So if you have doubts, questions or even just a feeling that there is something that bothers you then talk about it!