I don't own the official guidebook, but hell. Even if it is "official", there's no way I can consider it as such. Not after they mentioned Eren having romantic feelings towards Annie, which of course, Isayama denied later (but said it was probably his fault due to not being really clear).
The lower outlined red portion reads:
Eren concealed his faint love for Annie and fought with her in titan form.
Lol wut. Even Isayama denied that claim in his blog (last section of the post, before the comments):
I must have told the guidebook writer wrong so it’s my fault. I think Eren respects Annie but he doesn’t have love feelings towards her.
So many shenanigans.