I take it as “your communication assumes good motives” which is not “you assume good motives”

I think most people have good motives based on their world view and this will work.

Assuming good motives can help you uncover them.

For example the “asshole” at work who seems to be blocking you - they might have good reasons you can explore.

Of course their are liars, scammers, psychopaths. If possible cut ties otherwise you have to consider dealing with them tactically.

None if this is easy though!