Clarity is more encompassing than the notion of truth. Truth can be considered a special case of clarity, specifically when clarity is applied to empirical concepts or empirical theories. We can also use "truth" to designate coherence in logical or in other abstract fields of human knowledge. In that case it is also a special case of clarity, applied to the necessary logical relation that exist between certain concepts.
In all cases truth seems to be an example of clarity. However clarity encompasses much more than the usual concept of truth. For instance it applies to emotional states, motricity (being clear about how to dance something), etc. In fact, clarity is the ability to relate to anything, so, if we see ourselves as in relation to anything (the world, feelings, ideals, ideas, etc), it applies to any kind of such relation. It is in this perspective that I understand the role of clarity.