If you are honest to yourself, you will notice the presence of a compelling peaceful feeling and assurance about the man you intend to spend the rest of your life with, when you think of both of you living as husband and wife. If this peace is not present in your relationship, you may need to put all plans to take the relationship to the next level on hold till you get this assurance!
And the best way by far to get this assurance and to be sure you are taking the right step is to ask for divine guidance. If you have sought the face of GOD and still feel that doubt and uneasiness, that is GOD telling you "DO NOT GO THERE". Am very sure a lot of us know exactly what I am talking about.