What, he ended up promising it to her without any conditions? Shouldn't he have at least made it a condition that he would be the first one to hear it played since it seems to affect him so much?
Even if he didn't get an actual promise out of her, he's made a connection to her and the Youlan Palace and i think that's even better than a single promise to find An Xueyan.
@raos044 It's a bit author trick to prepare the next arc. Introducing new allies (power+1) and new know it all about future enemies during the intermission. + One of those dude at the meeting may be on the evil side later.