Belief in God’s providence does not mean that God always answers our prayers affirmatively. He answers all our prayers, but he answers some of them negatively, and for the very best reasons.
There’s a story of a shipwrecked sailor on an inhospitable island. He was dying of hunger. One day a box was suddenly swept to shore and he rushed eagerly to open it. But he fell back to the ground with bitter disappointment, because the box was full of gems and pearls. It was filled with riches that could not sustain his life.