Truth

'Truth' is the conformity to fact or reality. The exact accordance with that:

which is,
has been, or
shall be.

And speaking "the truth" means speaking conform the facts.

From Webster's 1828 dictionary:

TRUTH, (noun) Conformity to fact or reality; exact accordance with that which is, or has been, or shall be.

'Conformity to fact'

Examples

Two examples of:

recognizing the truth, in conformity to the facts, and
acknowledging the truth:

'Joshua was old and stricken in years;
and the LORD said unto him, Thou art old and stricken in years'

'Then I turned, and lifted up mine eyes, and looked, and behold a flying roll. And he said unto me, What seest thou? And I answered, I see a flying roll.'

Recognize truth

Whether you recognize truth depends on your standard of evidence: what amount of facts do you need to be persuaded?

Check your standard of evidence.