I found chapters 74-86 in the novel on wattpad if you have an account. https://www.wattpad.com/story/218656426-who-made-me-a-princess-continuation
and then chapters 88 and on are in this link:
https://www.wattpad.com/story/216931394-who-made-me-a-princess-s3
*theres one chapter missing but ╮( ̄▽ ̄)╭
you can probably find it on readlightnovel.com
that's where I find all these kind of books, if that doesn't work try NovelFull or simply just look up "Suddenly Became a Princess One Day novel" in the google search bar. The first thing that usually pops up is http://www.novelupdates.com go there scroll down it should show you chapters and the person who translated it, tap the chapter and not the person who translated it or else it will send you to their info page, or you can go to wattpad like the person above suggests. This works for a lot of novels.
Does anyone know if theres a translated novel of this that's completed? i saw some chapters on novel updates but the manga is already way ahead, i was hoping i got read ahead using the novel.
Thanks in advance! (▰˘◡˘▰)