True repentance, indeed, appears often to be very slow, but the knowledge of pardon comes suddenly when the last known sin is forsaken, and the soul implicitly trusts in Christ and His blessed work and word. So with a Baptism of the Fire of Divine Love. We must first be purified, and then grow. First pure, then mature. Wash a babe, and it will grow quicker.
Washing is one thing, and growth is another.
Growth is enlargement - not destruction. It is useless to sow wheat to kill thorns. This entire cleansing must then, be repeated moment by moment. It is leasehold, not freehold. After this, indeed, and only then, can the Baptism of Fire be vouchsafed.