Complex sentence: Tanja tries to win her son back by trying to bring Ansgar to marry her, so they can win back custody of their son together and can enjoy the millions of the Lahnstein assets, because of a faked last will of Johannes, Hannes is the heir.
Split into simpler sentences: Tanja tries to win her son back by trying to bring Ansgar to marry her. So they can win back custody of their son together and can enjoy the millions of the Lahnstein assets, because of faked last will of Johannes, Hannes is the heir.