Jealousy is the art of injuring ourselves more than others. — Alexandre Dumas. French writer and dramatist (1802–1870)
A person who doubts himself is like a man who would enlist in the ranks of his enemies and bear arms against himself. He makes his failure certain by himself being the first person to be convinced of it.
Pure love and suspicion cannot dwell together: at the door where the latter enters, the former makes its exit.
How is it that little children are so intelligent and men so stupid? It must be education that does it.