The knowledge that we are called by God who will never allow us to be overwhelmed by difficulties makes us hopeful. Pope Francis says in that homily of July 2013: "I would say forcefully: always know in your heart that God is by our side; he never abandons you! Let us never lose hope! Let us never allow it to die in our hearts!" He goes on to say that the evil never gets the upper hand. "The one with the upper hand in God, and God is our hope."
I know in my own life that it is the evil spirit that tries to tempt us to feel sad, discouraged or just lonely. Those feeling do not come from God and we need to reject the thoughts that take away our joy and peace. If we reject such thoughts and feelings immediately, we find that God is with us and He wants us to be joyful. Hope and joy go together.