Set in Stone (слэш)

What do you do when you write about a certain six thousand year old consultant so much in your letters that it somehow convinces your entire family you're not only dating each other, but that you're also engaged?
In Childe's case, the answer is plain and simple: he goes along with it, of course. Absolutely nothing can go wrong if he makes a contract with the God of Contracts, vowing that the two of them will pretend to be lovers for the duration of his family's stay in Liyue. Afterwards, they'll return as normal and speak no more of this mess. No feelings or complications involved whatsoever.
Contract accepted. A fool-proof plan set in stone. Right?