There is a general rule concerning all special graces granted to any human being. Whenever the divine favor chooses someone to receive a special grace, or to accept a lofty vocation, God adorns the person chosen with all the gifts of the Spirit (omnia charismata donat) needed to fulfill the task at hand.
This is a beautiful and important teaching. Hearing something like it when I was in an early spiritual impasse helped me to shift my understanding and keep going. The teaching implies that the spiritual life is not about effort, but consent. We don't have to reach up and squeeze grace out of some stingy deity. All the graces we need are there; it is only our inability to let go and accept them that holds us back from sanctity.
I often mention this teaching to the couples I am preparing for marriage. They have been given each other as a special and unrepeatable vocation in the world. Unfortunately, it is a vocation without a high success rate. They need to believe that all the graces they need to succeed are there for them, if they only stay close to the God who delights to join them as one.