Communication plays a very important part of any relationship. You have to be able to talk openly and honestly with each other. Also lying has no place in any relationship. Trust is needed also because without trust you basically have nothing.
Most of all is Trust and then respect, understanding and where there is love than these are natural but if one of them is missing that means you do not love the person. So clear all doubts and be with the person you have intended to be with for ever.