Denial means we didn't let ourselves face reality, usually because facing that particular reality would hurt. It would be a loss of something: trust, love, family, perhaps a marriage, a friendship, or a dream. And it hurts to lose something or someone.
Denial is a protective device, a shock absorber for the soul. It prevents us from acknowledging reality until we feel prepared to cope with that particular reality. People can shout and scream the truth at us, but we will not see or hear it until we are ready.
We are sturdy yet fragile beings. Sometimes, we need time to get prepared, time to ready ourselves to cope. We do not let go of our need to deny by beating ourselves into acceptance; we let go of our need to deny by allowing ourselves to become safe and strong enough to cope with the truth.