How does Charisma affect your negotiation skills?

Solution 1:

Even yellow isn't 100% guaranteed at high charisma levels maybe at 10 but I have seen failures at 7. Basically it is similar to Fallout 3 they just don't show the percentages anymore. Even with 10 on occasion you will get failures, so the black widow/lady killer perk is still useful even if you have 10 charisma. Best thing to do when you go up against speech checks is equip some items that boost charisma, (keep a few with you) save the game before you attempt the speech check, and if necessary use some chems to boost the charisma even further. Remember you can get it over 10 with items and stuff so may as well use them. (Also if you already have 10 and you pick up a special raising bobble head it will raise it to perm 11)