The explanation is that they're very clearly in love, but Zizhen wisely does not voice that opinion. Besides, Jin Ling did point out how convenient it was that he overheard the things he heard, so maybe it was all just an act.

(It didn't seem like an act)

"I don't know." he admits with a sigh - he's never had to deal with anything like this "but I bet your uncle does, I mean he rebuilt the Jiang sect himself, I bet he had a bunch of enemies trying to take advantage of him while he was weakened, and... well, Nie-zongzhu probably had a lot of enemies too, people who thought they could do better than him, he had to deal with them, right? I know you don't like him, but you could use his expertise, right?"

~~~

Wuxian gives Jingyi an assessing look - he's not entirely sure he wants to encourage the kid to violence and intimidation, but he can also see the determination in his eyes.

"It took a few hours," he admits "I can do it quicker, now I know how, but we're still talking an hour or two... Jingyi, you shouldn't go alone... you're her target, we can't trust she won't try and take advantage."

He maybe shouldn't have said that so bluntly, woops.