The person who understands alternatives usually understands the conversation differently.

Whoever has mapped the alternatives is having a different conversation than whoever has not. They know what each outcome is worth, when to stop, and which threats are real, so the same exchange gives them information rather than anxiety. That understanding is quiet and it changes everything about how the discussion goes. It is also the part you can do beforehand.

Spend your preparation time on options rather than on arguments. Know what you will do, what they will likely do, and what each is worth. Then the conversation becomes mostly a matter of listening.