DF - 3-4, 6, 12 - Faith is an internal acknowledgment of truth.

Doctrine of Faith for the New Jerusalem

DF 3-4, 6, 12
The reason spiritual things can be comprehended is
that in respect to the understanding
a person may be uplifted into the light of heaven,
in which light
none but spiritual things appear,
and these are the truths of faith.
For the light of heaven is spiritual light.
This then is the reason
why those who are in the spiritual affection of truth
possess an internal acknowledgment of truth.

. . . faith and truth are a one.
For this reason the ancients
(who from their affection for truths thought more about them
than the men of our time)
instead of saying Faith, were accustomed to say Truth.
For the same reason also truth and faith
are one word in the Hebrew language, namely Amuna or Amen.

If any one should think within himself, or say to some one else,
"Who is able to have the internal acknowledgment of truth which is faith? not I;"
let me tell him how he may have it:
Shun evils as sins,
and come to the Lord,
and you will have as much of it as you desire.