You said it best "FduToit" there is no way you can tell from the beginning. In the beginning if you like them and they like you, it seems everything is perfect. As time goes on we'll see things that may or may not bother us about them. The truth is when you do find out the things about someone that like and dislike but you can tolerate them and you desire them and they desire you, believe it or not that's a great place to be.
Never rush into a relationship based solely on your feelings, however never ignore your feelings, time will always give you a better picture who you really want and need and who wants and needs you.
Love is powerful and possible to obtain. Never give up on the most important reason for living and that is to be loved and to love.
More on relationship in my hub