Self Esteem & Relationships

My fiancé just left me a few months ago because he felt I was choosing the military over him. Ever since he left my self esteem/worth has been incredibly low. I have finally met a guy who constantly calls me beautiful and tells me things that make me incredibly happy (I.e. How he wants to be with me, how lucky he is to have met me, how smart and amazing I am, you get the picture). While it is wonderful and all I don't know if I can fully trust what he says or if he is just saying that to use me. I know if I bluntly ask him he could just say what I want to hear. I didn't know if you ladies, or guys, on here might be able to give me some advice on what to do/look for.