Yan Zisu didn't plan to hide any longer, because she already wanted to explain to you, just previously afraid you couldn't accept it.
Now, all the strengths you've shown prove that you're definitely not an ordinary person. This makes Yan Zisu feel relieved because she thinks she's gotten closer to you, even in heart.
"That strange sound continued for a while and then disappeared, until a month ago, after you sent Dad to the hospital. One night I returned home and saw a sparrow perched on the bamboo pole for drying clothes. At that time the sparrow chirped at me twice, and...I actually understood what it meant."
Saying this, Yan Zisu again bowed her head. If others hear this, they would surely say she was dreaming, and in the best case; if malevolent, they'd say she's a Madman.