I have been playing for a while now, but I'm not sure how the skill check with axii in conversation works. The description for the delusion skill says
Also increases the effectiveness of Axii in dialogues.
Does this mean that I will always succeed with axii against weaker opponents, or that I only have a higher chance of succeeding? That would mean that there is a chance of failure even against the weaker opponents.
I'm not that far in the game so I haven't encountered (in my opinion) strong willed characters that had the option available during a conversation so I could test this. With one point in delusion the skill seems to always work against the thug outside the first tavern in White Orchard.