truth=beauty? Beauty and truth are words we use to describe particular things. Discussing the words truth or beauty in isolation, (in themselves so to speak), is usually circular and vague and unrewarding. What is truth? Who knows? Beauty? Ditto. We have a range of theories, epistemologies and/or metaphysical views to choose from.
It is generally more useful to look at a specific example of something - a proposition about the world, say or an artwork, for instance and then ponder whether this is true or not, or beautiful or not respectively. For me, truth and beauty are just words which don't have anything more to them except, associations, traditions and usage. The idea of an 'eternal truth' seems to me to be vague and suggests a remnant of Greek philosophy and not something I accept as useful. I totally reject any intrinsic connection between truth and beauty, that's a bit of old fashioned romanticism right there. But I do think being told the truth at the right time can be a beautiful thing