3rd Level Diplomat Min-Max
- Half-Elf (18 Cha, 10 Int)
- Marshal 3 (2 Minor Auras (+4 each): Motivate Dexterity, Motivate Charisma; Skill Focus (diplomacy))
- Negotiator Feat
- Complementary Insight (CV)
6 ranks (Diplomacy)
5 ranks (Bluff, Knowledge (nobility and royalty), Sense Motive)
Speak Language (Celestial, Infernal, Abyssal)
6 (ranks) + 9 (synergy) + 3 (skill focus) + 2 (negotiator) + 2 (racial) + 4 (charisma) + 4 (motivate charisma) = +30 without equipment
Potion of Eagle's Splendor: 300 gp (adds +4 to charisma, raising overall bonus to +34).
If instead you go with Marshal 2 (for the skills) with a level in Psion (telepath) with the Psicrystal Affinity feat (bonus from Psion 1), the bonus is now at +37.
Throw a Telempathic Projection on the subject, and not only do they start out at a higher attidtude, but you then get another +4 bonus in Diplomacy versus them, so you're now at a +41 bonus, but if you take 10 as a full-round action, you get get a hostile creature to helpful in one standard action and a full-round action.
that's about my limit at 3rd level, sorry.