Hi! As long as the book is concerned, the truth was a secret that died with Jungkook. But as writers, we're still unsure whether he did or not. We planned for him to love Anna but Jungkook's character made some choices that made us question whether our plan would even work out or not. So, the answer may be whatever you want it to be. But to me personally, Jungkook did not love her the way Anna would've wanted him to. I hope that somewhat answers your question.
-sae