Someone asked me this question and I have answered the question in the following way:
Truth is truth.
There are some basic elements and aspects that cannot be defined by further or more basic something. So, truth is truth. It reveals intuitively.
When ‘truth’ is the definiendum, there cannot be any suitable definiens for it.
Still, we can define truth as the opposite of falsehood.
We know, this sort of definition is circular. But we have no other way. We have to start from some point and to assume something from that position.
From this point of view, truth is the default position and any sort of contradiction with the truth-position, we call it as falsehood.