"No time at all" is not the truth. Ellis doesn't need to call her on that, because it changes nothing. Wysteria did something kind for him when she hadn't needed to, and Ellis understands exactly what it is to want as little attention called to that as possible. Is this garden not something similar?

At the question, Ellis reaches over to draw one of the buckets over to sit on. He has some sense that whatever she's going to ask might be something he'd rather not answer, but on the off chance it's about the book, about one turn of phrase Ellis had read a thousand times but never paid particular mind to while Wysteria had plucked it out to consider how it relates to the Chantry or some historical event or how it may be an allegory for this or that, he'd like to be comfortable.

"I think so," he answers her, elbows set on his knees, hands folded loosely between them. "I can't promise I have the answer you're looking for."

Which tends to be the case sometimes, when they talk about literature.