Blessed Alan de la Roche says that a nun who had always had great devotion to the Holy Rosary appeared after death to one of her sisters in religion and said to her: "If I were alowed to go back into my body, to have the chance of saying just one single Hail Mary - even if I said it quickly and without great fervor - I would gladly go through the sufferings that I had during my last illness all over again, in order to gain the merit of this prayer." This is all the more compelling because she had been bedridden and had suffered agonizing pains for several years before she died.
Taken from 'The Secret of the Rosary' by St. Louis De Montfort