The fourth Beatitude reads:
“Blessed are those who hunger and thirst for righteousness, for they will be filled”
Pope Francis cites intensity, and I think that differs from a person who merely wants or prefers something:
77. Hunger and thirst are intense experiences, since they involve basic needs and our instinct for survival. There are those who desire justice and yearn for righteousness with similar intensity. Jesus says that they will be satisfied, for sooner or later justice will come. We can cooperate to make that possible, even if we may not always see the fruit of our efforts.
I think a well-meaning person can desire world peace, for example. But perhaps such an individual fails to hunger if she declines to work for justice, or he neglects the ways in which he inflicts violence on others by word, deed, or omission. I think a thirst for justice involves a future condition in which a person knows and feels relief for others in the same way an athlete enjoys a shower or a rubdown after a competition–a far different thing than dragging oneself out of bed for a daily cleansing under the bathroom nozzle.
You can check the full document Gaudete et Exsultate on the Vatican website.
Catholic Sensibility 