At the end of Blood of Elves, Yennefer and Ciri have the following exchange (emphasis mine):
“What are you looking at like that?”
“At that tree. That linden tree.”
“And what’s so interesting about it?”
“Nothing. I’m simply feasting my eyes on it. I’m happy that . . . I can see it.”
“I don’t understand.”
Silence. No words. Humid.
What is the meaning of Yennefer's words? Is she remembering some fond memory with Geralt?
Please avoid spoilers of future books in your answers.