When you do not trust yourself, what you feel, and what you know, you will expect people to be who they are not. You will hope against hope that they will do things you already know they cannot do. You will expect them to be who you want them to be rather than trusting what you know about who they are and what they are capable of doing. This is not trust. This is magical thinking, and engaging in it will set you up for a big letdown. Trusting yourself is important when dealing with others because it protects you from repeated violations and devastating heartbreaks.