The Frankfurt striker netted the only goal of the game on 33 minutes when she raced onto Anja Mittag's clever pass and trickled a low shot beyond Kristin Hammarstrom.
The reigning champions came into the last four contest as self-proclaimed underdogs but dominated from the kick off with Marozsan heading a clear opening well wide before Simone Laudehr's fierce header was tipped onto the post.
Sweden did have their moments and Lotta Schelin fizzed inches wide before seeing a second-half strike harshly ruled out for a foul on Annike Krahn.
The hosts improved greatly following the interval with Josefine Oqvist unlucky to hit the post with a miscued cross while Kosovare Asllani failed to connect with a gilt-edged opening inside the six yard box.
The Swedes continued to push right up until the final whistle but Germany held firm to book their place in Sunday's final where they will face either Denmark or Norway at the Friends Arena in Solna.