In an earlier post (Faith and Charity) I worked out a model for attaining faith which is: belief, hope, faith. First we believe, or desire to believe, or have a particle of faith. We then act on our belief. Then, after investing ourselves in that belief we hope our efforts and beliefs will be rewarded. When the Holy Ghost affirms our hopes and beliefs we attain faith.
Faith is the assurance that comes from a witness of the Holy Ghost. Once we have attained faith, its assurance strengthens our hope and reinforces our belief. Thus, we cannot attain unto faith without hope, but without faith our beliefs and hope will not endure and grow.