Too good to be true? Good situations always SEEM that way if you had bad experiences before. You have to take people on a case by case basis. A man that cares for someone is pretty rare but not "too good to be true". "too good..." would be if some perfect guy living in Nigeria wants to send you a million dollars.
What you need to think about is if he wants to get real serious. How far would YOU like it to maybe go? If he were not serious about wanting to date and not just a booty call, he would not be buying flowers/perfume/etc.
He might be an old fashioned romantic. Don't blow it and don't question things. If you do, he will be confused and start to worry. Once you give someone a solid reason to worry about the stability of the relationship, things go downhill. Yeah people can speculate and dream up their own reason to worry but if the other partner has not done anything (like express their own concerns) then it will be fine.
There are a lot of assholes in the world. Too many people who just want to bed-hop. Too many people who want to date but are holding out for "Perfect" or just don't want to make any effort (which is why dating sites exist). this guy is making an effort. I still think he is being a "Nice Guy" but maybe he is genuine.
I am jealous.