Oh my gosh!!

Sammmeeee. I'm actually really happy the author made Siyeon get mad! I get that this is fiction, but who the fuck would just act like it's no big deal to get background checked by your own partner? lol I realllllly hope the author won't make Siyeon let it slide this easily. Not asking the author to make Siyeon petty, but what Taekyung did is straight up toxic.
Personally, although I still enjoy the story and love the sex scenes, I'm starting to want Siyeon to leave Taekyung for good before things get even more creepy and hurt him in the end ;-;.

It's actually a really fucking good idea to figure out if your date is a con artist, or a domestic abuser or any number of fucking things they could be hiding. Most people look up their dates on social media at least before getting involved. Trust isn't quick or easy to earn.

Looking up your date on social media ain't really the same stuff as running a background check on someone. What you put on social media is what you choose to put. It's information you choose to divulge on your own free will. Running a background check is on a whole other level. Looking at your date's social media is actually a good thing to do. (=・ω・=) At least you somehow know whether the person is legit or not, although it's not always the case.

But both are for the same person and if anything social media is just more invasive with less relevant information than a background check that would show criminal background and so on. Do you just automatically trust anyone willing to date you? Seems pretty naive...

I absolutely agree that social media gives less relevant information! And it's absolutely true that a background check will give you much more relevant information such as criminal background as you mentioned. It is, indeed, way more useful to determine whether someone or not is worth your trust. Social media, in contrast, can just be a pure bunch of lies. But I honestly and seriously do not understand how social media is more invasive than a background check. In my opinion, it makes absolutely no sense, as when you look at someone's social media, you look at information the owner of the account chose on his own free will to share with others, while when you run a background check, you look at someone's private life without their consent, you look at stuff that person had no choice over deciding what he/she was willing to share.
To answer your question, I do not automatically trust anyone willing to date me, no, in fact, I have trust issues. But I don't believe that going behind that person back and looking at their private life without their consent is the right way to start a relationship. If anything, it might just end up making them not trust you in return, and more inclined to hide things from you, because they won't trust that you will respect their feelings and choice anymore (i'm using the term "you" here but I'm not actually talking about you, just using it as a general term).

I'm not saying that I personally trust everyone I date. But some people can be completely psycho and have a clean record. I'm sure our little contract killer doesnt have murder on his stuff. But what makes u realize that even he knew he was wrong for it was the way he wanted to hide it. But his big mouth gave him away (〜￣△￣)〜 that's why I said I understand but on the same token. It's not good relationship building to be that paranoid to background check. Especially if ur gonna beg the person to stay. Like if he was that concerned he should've done it when he first moved in like most places do. But you know why he didn't? Or better yet to ask why he did it so late in the game? It's because he got impatient and instead of waiting; For him to talk he wanted the tea early. If he had done it when he was first moving in I would've been understanding since it's a stranger in ur house. But to do it with the intentions to snoop on ur lover to me is just not okay.