If you say you will do something and always follow through or are always there for support or a shoulder to cry on, you are a trustworthy friend. If a friend tells you something in confidence and asks you not to say anything, you need to keep that locked up tight in your brain vault. When friends find out that you told someone about something that was supposed to be private information that could be grounds for dissolution of that friendship. Friends need to know that you will keep information private and that you are a person of your word.
When you are going through a rough patch, it is important to have someone to turn to. You may have a significant other who is part of your support systeml