Blessed are the Pure in Heart

Now this beatitude is unlike all the others for all the others are fairly straightforward and self-explanatory…this one seems vague and subject to interpretation. I, generally speaking, know when I have behaved meekly or have shown mercy, but what does Jesus mean by a “pure heart”? Note, Jesus did not say “Blessed are those who purify their hearts”, but “Blessed are the pure in heart”. The “pure in heart” is something a person is…how does one get to be one of those folks? What does it mean to be pure in heart and if my heart is pure in what sense will I “see God”?