Title: Bishoujo Senshi Sailor Moon R: The Movie
English title: Sailor Moon R: The Movie - The Promise of the Rose

When Mamoru was little he gave a rose to a little boy named Fiore. Fiore promised that one day he would bring Mamoru lots of flowers. Now Fiore has come back to earth but his intentions are not merely to fulfil a promise... 

(Source: ANN)