[ Oh, he doesn't know.

He hasn't gotten there yet. ]

Wei Ying... there is something I never told you.

But you must promise me if I tell you, that you will act no differently once we return to our homes.

[ Our homes, because he doubts that the other Lan Wangji will appreciate this one having to deal with Wei Ying knowing this and springing it unsuspectingly on Sizhui. ]