In his The Science Before Science, Dr Anthony Rizzi defines truth in this way (note: emphasis is in original, and I use the convention that a three dot ellipsis means I stayed in the same paragraph and a four dot ellipses means that I continue in a new paragraph):
"Hence, truth is conformity of the mind with the thing under consideration. Truth is conformity of the mind with reality....Truth is being as viewed from the standpoint of intelligibility...Each of the transcendentals is interchangeable, or, said another way, they are 'being" looked at from various viewpoints....All things are true insofar as they are."
It is maybe worth comparing this to Adler's definition/explanation of truth (which I previously mulled over), namely that it is the "correspondence between the mind and reality." Now we turn to a second statement: "there is no truth." Some  interpret this by saying that this is a statement akin to "there is no God" or "God is dead" (after all Christ does tell us that He Is the Truth in John 14:16). Well and good, except that God Is, that is to say, He is also the source of all existence: He Is His existence , but as traditionally understood by Christians (and some others) this also means that He Is existence, that is that all things which exist exist through Him.
"There is no truth" becomes a denial not only of God, but of existence itself. Barring this, it becomes at the very least a denial of intelligibility, or of the mind's ability to conform with reality. But if there is no intelligibility and no ability of the mind to conform with reality, then what purpose does science, or philosophy, or even knowledge broadly serve? To believe the philosophy that there is no truth (or Truth) is to undercut that very philosophy. A philosophy which says "there is no truth" is pointless at best, and self-refuting at worst: either way, it is unworthy of belief.
 The alternative is to take this statement at it face value and declare that there is no such thing as truth, meaning that the statement "there is no such thing as truth" is itself not true.
 Or, to return to the passage quoted above, truth is interchangeable with being, and also with reality, since these things are among the transcendentals. The transcendentals include: being (ens), reality/thingness (res), unity (unum), identity and separation ("identity as something apart," aliquid), truth (verum), goodness (bonum), and beauty (which is the goodness of truth).