In pathfinder what does someone roll in order to seduce a woman or a man. Is it raw charisma or is it diplomacy or is it something else?
"Seducing" could fall under one or more of many different checks, depending on what approach the character (Sam the Seducer) is taking. How susceptible the target is to any approach (if any) will depend on the target and what kind of game the GM is trying to run. If Sam is trying to seduce an Ogre trying to murder him (without the aid of magic), no roll will save him unless the campaign is a semi-silly one. Some examples follow, and a combination of several checks might often be appropriate.
If Sam is trying to be a good conversationalist, Diplomacy.
If Sam is trying to overstate his status, Bluff.
If Sam is trying to serenade his target, Perform.
If Sam is relying on his natural good looks, Charisma.
If Sam is trying to make himself look more appealing than he actually is, Disguise.
If Sam is trying to impress his target by showing understanding of an academic target they find fascinating, Knowledge.
Sense Motive could help Sam figure out which approaches are working and which are not.