Complex sentence: Leontine wrote to Vienna to try to secure this contact and in August Metternich received a warm letter from Franz Joseph; whether sincere or not, it buoyed Metternich considerably.
Split into simpler sentences: Leontine wrote to Vienna to try to secure this contact, with success. In August Metternich received a warm letter from Franz Joseph and, whether sincere or not, it buoyed Metternich considerably.