This is a perfect example of how posting a single verse teaches you nothing. Nobody is pure in heart but if you're covered by the blood of Jesus then you have the imputed righteousness of Christ.

Let's look at the beatitudes. You'll see that each one of those is a characteristic of someone who's saved.

(Matthew 5:3-12 NIV) "Blessed are the poor in spirit, for theirs is the kingdom of heaven. {4} Blessed are those who mourn, for they will be comforted. {5} Blessed are the meek, for they will inherit the earth. {6} Blessed are those who hunger and thirst for righteousness, for they will be filled. {7} Blessed are the merciful, for they will be shown mercy. {8} Blessed are the pure in heart, for they will see God. {9} Blessed are the peacemakers, for they will be called sons of God. {10} Blessed are those who are persecuted because of righteousness, for theirs is the kingdom of heaven. {11} "Blessed are you when people insult you, persecute you and falsely say all kinds of evil against you because of me. {12} Rejoice and be glad, because great is your reward in heaven, for in the same way they persecuted the prophets who were before you.