Much more than a feat, this is a "class feature" that paladins get in D&D once they are of enough level (like Uncanny dodge for rogues), level 2 in D&D (5 in FK?)
Paladins get a bonus to all their saves equal to their charisma bonus.
Example: A paladin with 16 charisma would get a +3 to all their saves (fortitude, will, reflex),
A paladin with 10 charisma or 8 charisma would not get a bonus to their saves (nor a penalty in the last case) Note: I don't think is possible to have paladins with such low charisma, but this is just an example for illustration purpose.