Assertiveness is a virtue that anyone can develop with practice
With trusted people, I find its best to default to a non-violent communication style[1]. Express your feelings with "I" statements, etc. "I'm feeling X". Believe the other side has positive intent (ie 'hanlons razor'). Express the 2-way nature, and understand feelings can arise for many reason that may not be anyones fault.Recently I had a conversation with to a colleague where I expressed their earlier perceived 'pressure' made me feel my relationship with them was "transactional". And I felt like my value was about the work I did, not me as a person. I reiterated throughout I didn't think it was their intention. I expressed that this has as much to do with my personality & baggage with how I perceive comments that might not bother others.I didn't do it perfectly (this is a hard skill to cultivate). But... we left with a better way to communicate. "OK Doug reacts to X statements a bit roughly". On my end, I take accountability for maybe overreacting to X types of statements, and taking a deep breath and being as forgiving as I can. Most importantly our relationship and trust deepened, and we'll work more effectively together...1-https://en.wikipedia.org/wiki/Nonviolent_Communication