So Boaz took Ruth, and she became his wife. And he went in to her, and the Lord gave her conception, and she bore a son. Then the women said to Naomi, “Blessed be the Lord, who has not left you this day without a redeemer, and may his name be renowned in Israel! He shall be to you a restorer of life and a nourisher of your old age, for your daughter-in-law who loves you, who is more to you than seven sons, has given birth to him.” Then Naomi took the child and laid him on her lap and became his nurse. And the women of the neighborhood gave him a name, saying, “A son has been born to Naomi.” They named him Obed. He was the father of Jesse, the father of David.
Instead of famine, "a nourisher"
Instead of a strange land she was now among her own people
Instead of mourning "a restorer of life"
She had lost sons now a daughter worth "seven sons"
She had no heir, now a grandson... an heir indeed
And no run of the mill heir at that; rather, none other than David would come from her new family and ultimately the greater than David, the Son of David, Jesus Christ.
Had the Lord brought calamity upon Naomi, well, yes He had. For a season she languished under the "dark Sovereignty of God as God worked behind the scene to get a Moabite woman into a particular field to meet a particular man at a particular time; in order that the ultimate plan of God could move ahead.
Naomi had an important role in the fulfillment of God Eternal plan of redemption for mankind. I do not think that she is in heaven now still upset at God for what He saw fit to put her through.
Lord give us eyes to see and appreciate the bigger picture and your sovereign work in our lives.