When religious scholars attempted to translate the Bible into English, they used the word "know" for sex. As a hormonal adolescent, I recall giggling anytime someone talked about "knowing" someone else as I mentally applied the Biblical connotation. To really know someone is a very intimate relationship that spans various aspects of the self.
Today, people often recognize that those judging or admonishing them do not KNOW their whole self. There is more to their story than what others may see or think that they know.
This applies to relationships, family, work, and the community. The amazing thing about people is that they are an endless universe of mystery. Someone may have allowed you to visit certain planets in their universe, but not them all. Life is not long enough for you to know everything about anyone. People are constantly evolving and growing beyond our ability to keep up.
When trying to get to know someone else, there are layers to intimacy any how deeply they allow you to venture into their universe.
We start with the least threatening, least personal aspects and work toward the most personal vulnerable parts. This takes time and effort, for all involved.
What gets in the way of intimacy?
Fear - "What if....?"
Pride - "They don't deserve to know me, it's not worth my time and effort."
Pain - "The last time I allowed someone to know me, I barely survived it and it still hurts."
These are all valid feelings when entering into a new level of intimacy with someone. There are no guarantees that the other person won't hurt you, reject you, or turn out to be an unsuccessful relationship. What is guaranteed is that if you keep up your walls, you never have the chance of having someone truly know you.
What can I do?
Begin small. Start with the least threatening and decide when/how to allow deeper knowledge.
Be aware. Check in with yourself mentally and emotionally: "How is this going?"
Be honest. There is nothing wrong with saying, "I'm not ready to share that yet."
If someone is willing to put the time and effort into getting to know you, they will respect your boundaries and pace. If they don't, they won't.