Two women talk for the best part of three-and-a-quarter-hours and Ryusuke Hamaguchi makes of it an unassumingly momentous miracle. “ All of a Sudden ,” the Japanese director’s gorgeous new feature, is the rarest type of film, not merely good enough to remind you what cinema can be, but great enough to remind you what life can be. At times, suspended in the long silvery skeins of conversation that thread through the magnificent screenplay (by Hamaguchi and co-writer/translator Léa Le Dimna) it achieves a kind of levitating grace, before depositing you back down in your seat again, a slightly different, slightly mended version of the person you were before.  Marie-Lou ( Virginie Efira ) is one half of the film’s radiant heart, though there is nothing half-hearted about her.…