
Sooooo.... She's only a little sister until she's hot? Ugh. ( ̄へ ̄)

She was only a "little sister" because she's Japanese, ergo, she had a baby face. She was also short and hid her curves under ill-fitting clothes, so he literally thought that she was a CHILD (maybe 14 at most). That was why his response upon finding out that she had matured physically was to ask how old she was.
It is very clear that he liked her as a person before inviting her to bathe in his room. This was not a post-boob development. However, he did not consider her as a potential romantic interest until after he found out she was of legal age to get married.
Though you are perfectly within your rights to dislike the ML for not being a lolicon. Whatever makes you happy.

Why are you taking my words out of context and making it sound like I wish he was a pedo? He's spent the last couple of chapters reinforcing just how much he saw her as a child then once he saw she had tits and she was 18 it was instantly "guess I can marry her now" and his view of her went from "look at this kiddo" to "she's a adult" right away with no time for adjustment of his mindset considering taking off her glasses doesn't mean she magically looks like an adult and loses her baby face. It's like old guys who have a countdown until girls turn eighteen and then say, "now we can bang bc ur 18"
And I'm not saying he's a bad character but the way it was written could have been a lot better if the author had taken like another chapter just to have him look at her actions and personality through the lense of an adult not a kid.

wait did they not do dat in chap 3??
in chap 3 he said dat she was different 2 other women & a mysterious person since he felt the urge 2 protect her & after learning bout her childhood, he already started questioning whether he wanted 2 help her coz of protection or something else. & during the time he thought she was a kid he said he felt no confident in sending her off when she becomes an adult

It's was chapter 4, not 3, and chapter 4 he still thought she was underage for the majority of the chapter. He said she wasn't like other women compared to the ladies who liked his title and hero status that fawned over him. He said he wants to protect her bc she's defensless aka naive and once again... He thought she was a minor.
Yeah he had that inkling he had a crush on her, but it jumped from "what's this feeling?" to "love and lust" after copping a glance at her tits and realizing she was legal.
I'm saying I wish he had that chapter to be like "wait do I really like her is that what this feeling is? Yeah it is. " instead of that instant jump from "ehhh maybe there's something to omigod I love her" all within four pages (technically 5 but one page was all pictures of mostly cleavage)
Once again, I do like this story well enough for what the story is which is an overtold cliché, but it all feels a bit too rushed.

hmm i think it wasnt because she was hot but it was because she was not a minor.... usually asian traits make them look younger so in the beginning he thought she was a minor and treater her like a little sister but when he notice she isn't a child he started to see her as a women and then fell in love with her personality and traits... it just happens that her breasts was the part that made him notice her age
28 chapters in and J is still an asshole#-.-)