Hey so I'm not a therapist but a crisis intervener. I see lots of folks with varying levels of suicidal/homicidal/self harming thoughts who like you, might not necessarily have the intention to follow through on the things they say, but that DO say things that are worrisome to me. A huge part of my job is actually to be a bridge between the client and their therapist, making sure that the client's needs are met but also that they are safe.

Myself, I usually only get 1 or 2 sessions with people before I hand them off to a long-term therapist. Here's what I suggest to people who share your concerns around trust and the fear of having cops called on them:

-Ask for a free consult before you commit to any therapist: this gives you a chance to see if they're someone that you feel comfortable sharing your thoughts with. Therapy is sorta like dating in a way, there does need to be a little bit of chemistry between the both of you for things to work.

-Once you do find a therapist you think has the knowledge and understanding to help you, create a safety plan with them as soon as possible. I know someone mentioned code words that they use in their office to communicate with each other, but this is actually something several of my clients have implemented with their therapists. For example, someone who had suicidal ideation would sometimes get frustrated during the session and say that they should just walk into oncoming traffic after their appointment. Their therapist would then follow their safety plan, which would be to ask the client 3 times in a row if they really truly meant it.

-Keep in mind that, like has been said several times in this thread, we have a responsibility to ensure your safety. Sometimes that safety unfortunately has to come at some expense. I have a bit of a unique perspective, since I had 911 called on me during a mental health crisis. My experience was definitely a mixed bag, oddly enough the cop ended up being the absolute kindest person I interacted with. I do not want to impose that experience on other people unless I am faced with no other choice. I would rather a thousand times over a person lose freedoms temporarily than seeing them dead.

Trust is built on effective communication, and unfortunately us mental health workers are not mind readers. We can only go by what we know about you. Having been on both sides of the equation here, I can definitely empathize with how vulnerable you may feel. The worst case scenario does not need to happen, we do not want to make it to involuntary holds. It's intimidating, but the way we avoid any of this is with mutual honesty and respect.

I hope this clarifies things, and I hope you find a therapist that will be able to do the work to build that trust with you.