There was a translation version before, almost complete, and it was on wattpad but got deleted because the publisher found it. You can blame reposters in IG and twitter.
You can buy the raw (ofc Korean) in ridibooks, and auto-translate it since they have the feature. But ofc its machine translated, so more or less like google translate - painful, tbh.
However there is one translator in wattpad, but I'm not sure if they're still updating because I think they found another novel to translate. Here ya go:
https://www.wattpad.com/story/162868792-suddenly-became-a-princess-one-day
As for me, I read two versions of MTL, that link and also 84 pages of spoilers so pretty much I know how the story goes but not the deets.
there’s no completed english novel online (only the wattpad version is out there, but it isnt completed) ive read the korean version since one of my irls helps translate the chapters for me to read whenever i have a hard time understanding. (also ive asked her before, and she wont be posting any of the translations online sorry boys). the only completed novel is the korean version, so unless u know how to read hangul, u either have to read the novel forms online for spoilers, or wait ):

ngl i was pretty disappointed with how different the manhwa is to the novel ): the reunion with athy and claude was way more emotional and powerful (also, jennette wasnt even called in the first place which kinda pissed me off lol) basically, there was a celebration i believe which was used as bait to lure athy to the emerald palace to meet claude, lilly, and felix, athy teleported into the palace expecting to just meet lilly (though this of course was all set up by claude). athy tried to teleport away, though there was magic in the palace preventing her to do so (tho claude coughed up blood or somethinf because of it, cant remember all the details). felix and lilly left both of them alone, then athy started saying claude wasnt her dad anymore as she started to tear up, claude himself said that he didnt know why he wanted to keep her by her side, but he said he would do it until the day he died (even if he didnt regain his memories by then), then athy started crying saying stuff like why did he forget abt her (i cried at this part cause we can see athy break down) claude was hesitating, but he reached out to touch athy’s face to wipe her tears and said he hated seeing her cry and it ended like that (could mess up some of the chronological order tbh) i was so excited to see this scene only to see it completely cut off from the manhwa ):