
Awe man, there goes my hope for the dude to be respectful. The typical "I see you as an adult" line to a kid who admits and understands he's easily influenced and groomed by someone older (especially a male since he doesn't have a father figure). Also now it's definitely creepy how he took advantage of the kids family being big on skinship.
Honestly, had he said "I understand. I'll wait for the day you feel you would be comfortable with this and not just feel like going along with everything I say cause I'm an adult" and then been left the kid to figure things out in his own time, he could have saved this somehow.
Also, I seriously thought he's a student not a high school kid. The scene in the classroom should have tipped me off...

the older guy didn’t force the kid in any way shape form to do anything. you’re also acting like he had a huge influence on how the kid made his decision which he clearly didn’t. it’s stated that he even didn’t talk to him for a few days because he thought he had been rejected and the kid is the one who came to HIM saying that he actually liked him back.

I never said he forced him and being forced isn't the only way of being taken advantage of. And the kid came back cause mc suddenly got the cold shoulder. He's someone who admitted himself that he wavers easily in front of adults so of course he would feel like he messed up and come looking to make up.
And the kid literally told him he's scared of how easily he's influenced by mc and then mc went and influenced him by spouting bullshit like "in the world you might be a kid but in my heart you are an adult" (excuse the paraphrasing but that's literally what it boils down to), so of course he would be influenced (hugely, so yes the mc had a huge influence on him confessing) by mc's words and reply after being confessed to. That's grooming.
I mean, it's a manga so enjoy it as much as you like and you don't actually have to read into it that deeply since it's fiction. But if someone states legitimate concerns then just ignore them if you don't want to get into it.

In the first chapter the coworker definitely saw him cause he said "in that case I'll go on ahead" so either the author forgot that or the boy is no ghost but somehow erased his existence (maybe something happened to him while getting to know the mc and he decided it would be easier on everyone if he deleted their memory so they don't grief)

I think the prince's main issue is how everyone keeps treating him like some devil and therefore he doesn't trust anyone and just assumes she, too, if afraid of him. I would have trust issues too lol
Anyone, why does the first chapter say she is the third princess but then she says her little sister to the second princess?
Did I misunderstand something?

there are only 2 princesses from my understanding. she might be the 3rd child? idk. maybe she has a 2nd older brother, but so far I think the whole "3rd" thing was just a translation error.
╮( ̄▽ ̄)╭
the confirmed royal children were: older brother (went with her to meet the red-haired prince/fiancé), the MC, the younger sister (getting engaged to some other noble), & the younger brother (toddler-ranged age, the queen was holding him when the royal family saw her off).
If anyone touches the omega mc, I'm going to riot