I don't know that there is any way to really know that for sure. There are so many issues that have to be thought about and you don't truly know a person, in my opinion, until you do marry them. Once they are committed to you, their "true colors" seem to surface. Marriage is a serious committment and it is often something you think you are ready for when in reality, you are far from it. So, if you can't be 100% sure of yourself, then how can you be sure that your future mate is ready?