I Became the Fiancé of a Crazy Heroine망나니 히로인의 약혼자가 되었다

Those who wants to read
MC is like I am an extra. I should leave everything to original MC. Much like never die extra. Totally like never die extra. So if you hate that novel don’t read it

What's wrong with marrying a crazy girl unless she's the serial killer type

Read upto 8-1 Chapters.
I was interested in this novel because of the title, but as I continued reading I lost my interest.
MC still believe that everything will go according to the story he knows, even when he himself started to do things that was deviating from the story.
I wont talk about Crazy Girl.
And as cherry on the top the sentences are not interesting to read.

Kinda lame. It has potential, but the writing itself is shallow and the good ideas fall to poor execution. It doesn't help that the banter between the MCs is poorly written, leaving little to no incentive to read this one. Might be an issue in translation instead of poor writing, but considering none of us know Korean, it doesn't really matter. Overall, lots of potential that quickly just falls flat on its face.

I am pretty sure, as a romantic novel the MC was bound to make "smart" choices, and the author would explain "why" over and over again to force the idea that what he did is smart and logical but the circumstances worked against him or something.

The Protagonist is not charismatic and he is very self-centered and the heroine is just an ungrateful daughter.

story is crap. was interested in it at first but couldn't get in to the story

In the image he isn't holing the sword it was added on top of it and badly at that LOL

Man is the opposite of 'Don't stick your d*ck into crazy'

It's pretty much what you'd expect out of tropes like these but the characters are lively and not bland. The FMC isn't just a decoration so that's a plus, the MC is pretty good too since he doesn't think with his lower part, it's still early in the novel so can't really say much more.