Truly? Objectively?
If you want to maintain your agnosticism regarding objective truth, then you'd have to respond, "I don't know that either," and so on to infinity. But an infinite regress can never be actually completed, so in effect, no statement is ever completed and, therefore, no statement is actually made.
The only way to "refute" (actually, to avoid) the idea of objective truth is to remain silent (as Aristotle said).
You can't escape truth because God is Truth, eternal Truth.