You may not know the truth about the other person, and many times that's the case in life. But you know the truth about yourself. That's the most important part, and what helps you move forward.

You know you only had good intentions and meant well in all that you wrote.

You know you wrote to her about heavier subject matters out of a sincere belief that she can handle it (apparently she couldn't and not everyone can).

Knowing that you are a person with pure motives, who is capable of genuine friendships, is a great truth to hold onto.