Kekko desu（結構です） - yes, or no?

“Kekko desu” literally means “No, thank you.” However, it can also mean “that’s fine” or “wonderful,” depending on context. Originally, the kanji “kekko” referred to "assembling." Over time, its meaning evolved from "wonderful architecture" to "excellent," and then to "sufficient."

The core idea is "adequate," which can imply acceptance or polite refusal:

“Yes, that is sufficient” → Accepting something.

“No, I’m already satisfied” → Politely declining.

Japanese people prefer indirect language.