I just found out they made this book into a film! Quite a few years ago.

"TOKYO FIANCEE - Bande annonce avec message d'Amélie Nothumb"

https://youtube.com/watch?v=LZg8dxKrLJs&si=STomYuqiPVoG6eWt

It's not available here. 

This seems to be dubbed over in Spanish. 

"Romance en Tokio (Tokyo Fiancée) (2014)"

https://ok.ru/video/1567824153289