Who did hear Kane to say 'Rosebud'

Rating: Null/10 (27 August 2007)

If Kane died alone and saying 'Rosebud', who did hear him?
The film is based in the searching made by a journalist looking for the meaning of the most famous word in Film History but... How did he begin his search? How could he interview all known people of Kane asking for Rosebud? There was no one with Kane to hear his last words. Who did tell to the journalist the last word of Kane?
Though it's the best ever made film, the beginning of the film is weak... It's a story based upon a said word that no one never heard because there was no one with Kane when died.
(If someone die alone in a forest, who can search for the meaning of his last word? This last word never existed because none could hear it)