"Sometimes your heart needs more time to accept what your mind already knows"
At times people can't see what's right in front of them. Even if it's waving them in the face they still won't accept the obvious truth.
It could be about the way they feel about someone or about the way someone(people) is(are) treating them.
They stay in denial. Because if they stay in denial then that way they won't have to face and accept the truth. They know that if they do accept it then there's no going back and it could ruin everything.
You can stay in denial if you want but sooner or later you won't be able to run away from the truth any longer. And when you finally accept the truth it'll come crashing down onto you so bad that it'll ruin you.
But sometimes it's better to not accept the truth because you don't want to lose anyone that you love or mean a lot to you.
Or you could accept the obvious truth. Yes it could ruin things but it's better than being in denial and being confused.