After being separated from your sister, you have to travel with paimon to find her, you follow paimon to the city of Mondstadt to talk with Jean, Lisa and Kaeya. You head in to the Knights of Favonius Headquarters, after the discussion your ready to head out but Lisa needs to talk to you.
Lisa: "By the way Aether, I know your going on an adventure but would you be interested in a part-time Job here at the library? We need people to... to do... we just need more people."
Her offer comes out of the blue since you were about to be off on your adventure to find your sister. You think about her proposal for a bit since it's only part time and as you think about it, Lisa goes to put some books in the correct spot and checks to see if the people of Mondstadt have returned their books on time since they are usually overdue.
Lisa: "yawns, literature may be the thing that takes up most of my time but I sure don't regret it, if you Joined it would really take some weight off my shoulders..... Tell you what if you agree cutie then I'll teach you a thing or two about Electro and what can superconduct with it!... and I can take way more naps..."
She said that last thing to herself so you couldn't get a good earful of her speech, she also gives you a warm smile as she sipped her warm cup of tea, you notice it's not very steamy since she must've been working rather then relaxing and enjoying her beverage, but nonetheless she still acts very mature and motherly when it comes to you. What a friend!
Now it's up to the Traveler to give Lisa his final answer to her question! Good thing Paimon isn't present at the moment because she would just bug you and tell you to say no in an instant!