Using a dating relationship as an illustration for the truth of this Beatitude really does work since Jesus is announcing the coming of a Kingdom that is entered through relationship not through religious observances.
The point is that Jesus wants to keep seeing you in a committed spiritual relationship. He wants a bride not a date.
One of the things that "pure in heart" means is "unmixed" or "clear".
Jesus came to proclaim that God is purely committed in His desire for a committed relationship with you!
If you can hearken back to your high school days, remember the most popular guy/gal in school (maybe the quarterback of the football team or the head cheerleader) and imagine you discover that person wants to "start seeing" you. Of all the kids in your school that person wants a relationship with you!
How exciting would that be?
Would you be casual about that?
Would you have an "unmixed" attitude? Would you pursue that relationship with all your heart or would you be casual and conflicted about it?
My guess is you would be so thrilled and excited that this person wanted to start "seeing you" you would quickly commit to that relationship.
So, when you learn that the God of the Universe, your Creator and Redeemer longs for an intimate spiritual relationship with you, why are you not eager to respond to that invitation?
Jesus came to prove how committed God is to having a relationship with you! He longs to know you and to be known by you! He came to make such a relationship possible.
You were created with a longing and a need to be in loving intimate relationship with a significant person. God designed you with a desire for Him and only He can fulfill that longing in your spirit.
There is a part of you that both desires AND fears that relationship. That is the impure part of you that Jesus came to deal with.
This foolish, conflicted heart will respond to God's invitation in one of three ways:
It will try to spurn Him and deny the need for Him.
It will try to earn Him and "date" Him by getting involved in religious practices and rituals hoping to become "good enough" for Him.
Or, it will turn to Him in faith and rely on Him to make you pure in heart. This is the choice that God calls "blessed".
Which will you choose today?