Complex sentence: It was rare and uncharacteristic of him to display any rage, and was similarly rare for him to tell people about his doubts and inner misgivings, reserving those for only a small number of confidants.
Split into simpler sentences: It was rare and uncharacteristic of him to display any rage. Similarly, he rarely told people about his doubts and inner misgivings, reserving those for only a small number of confidants.