
Yeah, he's already in deep for Je-oh. That woman (can't remember her name rn, the former prostitute turned company owner) was his EVERYTHING and he already:
1. Didn't tell her about kidnapping Je-oh.
2. Directly went against her orders when she said to kill him after finding out that he kidnapped Je-oh.
He's definitely just playing hard to get and there's the layer of complexity addes in that he's in love with that woman, Je-oh is basically like forbidden fruit to him. Je-oh let that guy go to beat him up and he STILL didn't kill him. Like, wtf?! No, he doesn't hate him lol.

So basically the “ex girl” you’re referring to, Ms. Jeon, was a former prostitute who’s now a business woman, and in order to get higher placement in a company, she’s killing off people who ran the sex tracking ring that she’s from. The red head guy, Seong-rok, is the hit man for her and it’s implied that they were probably intimate at one point in the past. The relationship between them is one sided, Seong-rok, being the one who has feelings for her (and I’m assuming one of the motives for why he’s killing people, is to get Ms. Jeon’s affection/help her get out of something [?]).
So the black haired mc in the story Jeoh, is a sex worker, near the beginning of the story when Seong-rok went after his next target on his hit-list, the blonde guy, he ended up walking in on Jeoh and the blonde guy having sex. He ended up kidnapping the blonde guy and Jeoh so there would be no witnesses. Jeoh has been living in the house with Seong-rok since then and has feelings for him and is sexually attracted to him. Seong-rok has the blonde guy handcuffed in a room for majority of the story thus far, and hasn’t killed him yet as intended.
In the chapter before the latest one Seong-rok breaks down his hit list and plan to Jeoh, since he wants to help Seong-rok. There’s a target that he’s been trying to get close to for a while but hasn’t been able to because of security protecting him. He wants Jeoh to be a decoy and enter the building to his target, so that he can kidnap him too, but from Joeh’s lackadaisical behavior while listening to the plan, Seong-rok tells Jeoh he doesn’t think he is capable of seducing the blonde guy or the next target.
Out of spite Jeoh suggests recording himself seducing the blonde guy with the camera from Seong-rok’s tool box, to prove that he can be useful (and mixed with a little bit of teasing since he wants Seong-rok to fuck him ). So in this newest chapter you see Jeoh seducing the blonde guy, with a hidden camera placed in the room recording live onto Seong-rok’s computer what’s going down.
Seong-rok has been acting hard to get for the majority of the chapters towards Jeoh, and that’s only going so far because the more he’s around Jeoh he’s losing composure, him masterbating to the live video of Jeoh and the blonde guy, is an example.
I think it’s funny how some of y’all are acting surprised and I’ve even seen someone say they thought Seong-ruk hated Jeoh. Uh..girlies he’s playing hard to get HARD.