Oath Bound (-2 FP): [character name] is incapable of breaking an oath once they have knowingly given it. This only applies to the meaning and contents of the oath that they were aware of at the giving of the oath, not possible reinterpretations of wording.
Likewise, situations that involve agreeing without knowing all implied details, such as signing a contract without reading the fine print, do not enforce anything but what they thought they were agreeing to.
For 2 additional FP, any creature they make a deal with is compelled to uphold its side of the deal, being affected as they are. This cannot affect creatures immune to mental tampering. However, if the creature does not uphold its side of the deal, they do not need to uphold their end.