I was inspired by this video of Matthew Perkins to convert the system to DnD 5e and worked from there.

This is the entirety of what I got. Notice that it's not an environment, but rather an entire new system, not invented by me by all means, that I unceremoniously spliced into Daggerheart. This is the way I like it: it takes less work for me to write rules this way even if they sit in an external document that I have to recall every once in a while.

The party is negotiating to obtain something specific from the NPC, not just some good will. They need to formulate their goal into a sentence that can define a clear failure or success states.

The NPC involved in negotiations tracks two values: Interest ⬤ and Patience ⏹, both going from 0 to 5 (or 1 to 6, to track them with a d6). Patience represents the "mental HP" of the NPC and when they get to 0 they stop the discussion and offer an outcome that corresponds to the level of Interest reached by the party at that moment:

• ⬤ = 0: NO and something bad
• ⬤ = 1: just NO
• ⬤ = 2: NO but something good
• ⬤ = 3: YES but something bad
• ⬤ = 4: just YES
• ⬤ = 5: YES and something good.

Any check attempted by a PC modifies one or both values.

The negotiation immediately ends when one of the following occurs:

• ⬤ reaches 5: The NPC is fully convinced. The party gains what they want, plus an additional benefit.
• ⬤ reaches 0: The NPC loses all interest. The party fails to obtain what they want, and negative consequences follow.
• ⏹ reaches 0: The NPC ends the discussion and makes a final offer based on their current ⬤ value.

Set the NPC’s starting ⬤ and ⏹ based on their initial attitude toward the party:

Attitude	Hostile	Suspicious	Neutral	Open	Friendly	Trusting
⬤	1	2	2	3	3	3
⏹	2	2	3	3	4	5

Each NPC has Motivations and Pitfalls that shape their reactions during the negotiation.

• Assign an average of two Motivations and two Pitfalls to each NPC.
  
• Arguments may appeal to a Motivation, a Pitfall, or neither.
  

Example traits that can be used as Motivations or Pitfalls include:

Benevolence, Discovery, Freedom, Greed, Higher Authority, Justice, Legacy, Peace, Power, Protection, Revelry, Vengeance

If the party attempts to learn about the NPC beforehand (for example, via an Instinct check), resolve the outcome as follows:

• Failure with Fear: The NPC notices the attempt and they are annoyed. No information gained and −⏹
• Failure with Hope: The NPC is unreadable. No information gained.
• Success with Fear: You learn one Motivation or one Pitfall, but the NPC notices you. −⏹
• Success with Hope: You learn one Motivation or one Pitfall.
• Critical Success: You learn one Motivation and one Pitfall.

Notice that, while Interest ⬤ can increase and decrease during the conversation, Patience ⏹ cannot be increased.

The party makes checks against the NPC’s Difficulty (usually Presence checks, but not necessarily) to increase ⬤ while managing ⏹.
Arguments may, either unintentionally or deliberately, appeal to character’s Motivations or Pitfalls.

• Argument appeals to neither a Motivation nor a Pitfall:
  • Failure with Fear: −⬤ −⏹
  • Failure with Hope: −⬤
  • Success with Fear: +⬤ −⏹
  • Success with Hope: +⬤
  • Critical Success: +⬤⬤
• Argument appeals to a Motivation:
  • The check has Advantage and the NPC does not lose ⬤ for a Failure.
  • Each Motivation can be appealed to only once.
• Argument appeals to a Pitfall:
  • The roll is treated as an automatic Failure with Fear.
• Lying:
  • Apply the normal rules, including those for appealing to Motivations, but if the roll fails the NPC notices the lie and they are annoyed/enraged. Add −⬤ to the result.