"a clear truth" is correct and can be used in written English.
It is generally used when referring to a situation or idea that is both obvious and indisputable. For example: "The clear truth is that everyone deserves to be treated with respect."
Wendell Berry spoke to us, and so many others, because his essays, poems, and novels told a deep, clear truth about the place where we lived, about Appalachia and the South, with some of the most beautiful language I've ever encountered.
The situation called for that rarest of events: a government body saying the clear truth about something everybody already knew.
In "[t]he absence of clear truth" is a space that Chamberlin describes as the breeding ground for myths.
It is not the only moment when the curtains of experimental style part to reveal a clear, durable truth.
There is no way to avoid the clear truth that the act of prayer itself is an explicit command endorsement of a set of theological beliefs above all others.
Throughout all of this, the one clear truth has come from Cesare Prandelli.
It's not too much to ask that the president of the United States speak the clear truth about his policies and their implications.
Byron's desperate need for approval, which often led to all manner of histrionics when the necessary ego-rub was denied, was matched by an equally marked capacity for generosity and kindness.Poets, said Byron in "Don Juan", are professional liars, and though her "fountains are clear" truth must often "navigate o'er fiction".
But he says that no man will know the clear truth about such matters.
If in this examination they arrive at some clear truth from which the assumption follows necessarily, they conclude that the assumption is true.
