Eventually, in his dreams, the scene of Zhao Lingling putting the necklace into Lu Ning's bag even turned into Lù Yue'an putting the necklace into Lu Ning's bag to frame her.
He was uneasy, but he did not want Lu Ning and Lù Yue'an to be hurt because of this—he did not want either of them to be hurt.
Hence, he gave Lu Ning a school bag and asked her to take inventory of everything. If she discovered the necklace, she would take it out; if she did not, the necklace would be left in the old bag, and he would find a time to secretly send it back to Lù Yue'an. Then, there would be room for redemption.
Lu Ning didn't mention it in the morning, so she must have forgotten to check the side pocket. The necklace must still be in her old school bag.
He was relieved that she could change her bag.
If the necklace wasn't there, they probably wouldn't be able to do anything.
This was what he thought, but he still felt uneasy.
