This is more than a doctrine. This is something a man or woman must experience. Though the passage is specifically about the Jews under the Law of Moses who cannot see Christ is God incarnate, the principle may apply to other cases.
The classic hymn about turning the heart to Jesus is very apt and true:
"Turn your eyes upon Jesus,
Look full into His wonderful face.
And the things of earth will grow strangely dim
In the light of His glory and grace."
Perhaps the best way to turn your heart to Jesus is to simply tell the Lord Jesus that you love Him.
"Lord Jesus, I love You. I love You Lord."
The heart TURNS to the Lord Jesus Christ and the veil of darkness is taken away.
Actually the intervening veil is simply the inner eyes of the heart turned AWAY from Christ to see many other things.
And if you feel that you do not love the Lord Jesus and cannot really honestly say that you love Him? Then I recommend that you confess the HE loves YOU.
"Lord Jesus, the Bible tells me the You love me. Lord Jesus, I believe that You do love me."
The Holy Spirit is real. And if you begin to confess that Jesus loves you, pretty soon you in turn will also begin to love Him.
The best way to turn your heart to the Lord Jesus is to confess either that you love Him or stand upon the promise that He loves you and died for you.