When you have trust in the Almighty, you have peace of mind. Even in very troubled times, a person with this trust will be able to handle life without worry and sadness. He experiences joy regardless of how much he possesses. He does not feel a lack, and he does not worry about what will happen tomorrow. He feels intensely that when he has this trust, he has everything.
Moreover, even if he does lack something today, he does not worry about it. His situation is similar to a growing, successful company. Even if on one particular day no orders come in, they don't worry. They know they have the right product and eventually will make a large profit.
So, too, with a person who has trust in the Almighty. Even if he is temporarily missing some things he needs, he will not complain. He feels secure that the Almighty will send him all that he truly needs. He maintains an inner serenity because he is certain that his path is the path of life.
(see Rabbi Yosef Hurwitz of Nevardok - Madraigos Haadam - Bitachon; Rabbi Pliskin's "Consulting the Wise")