Work on your negativity and assumptions. There could be some past bitter experience maybe you were directly affected or witnessed someone being affected. Either way, that should not be the cause for not trusting people. You might be missing a beautiful part of your life.
Living as single, not trusting people, doubting others will only make your life more miserable. Think of your midlife crisis and old age get isolation.
Next Steps
Maybe a visit to a Counsellor will help you alter your thoughts and approach towards shaping your own life.