Help with magicaly enforced contracts Options

[ruinareu]

I did a forum dive, but didn't really find anything on this. I'm trying to do an NWoD+fanelines-> GURPS conversion, and most of it is pretty straight forward. The only thing giving me trouble is the core power of Changelings: the ability to make magicaly-enforced oaths and contracts in play. (Geniuses are a little tricky, but modular abilities and gadgeter(aspected) should be enough)

What does the hivemind reccomend for creating magicaly-enforced oaths in play?