How do u guys think the romance will start between them?.. Give ur predictions..

For me, I feel like she will see find out he is the intruder, and will question him about his purpose, though i don't think he will tell her his true identity..I feel like maybe she will accidentially see him mysteriously going somewhere like the NIS office & follow him..idk what i 'm really saying here..

you all tell me ur opinions...

 Stargazing:

As per FL, current ML is look alike of her first love. Let's see what did this current ML did in his past to hurt her or any chances ...current ML's twin brother was actually FL first love.

If this ML is indeed the first love then chances are there to see their past romance as flashback as well as new romance in the school. I think This time it will be ML to take initiate in the relationship.

Once ML 's true identity get reveal , I will write my theory on that.

Umm I think you are talking about some other drama. This has nothing of the sort 😂

No, u misunderstood smth..it said the fl saw her first love in him, this could mean that maybe just like how our heart flutters when we start to like someone for the first time ( romantically), the fl type was reminded of her first love by looking at him....or if they were to do it like this he may actually be her first love maybe when they were young..(u know how kdramas do their things)..

Do u get it???

This article seals the deal of them having a childhood connection : https://www.soompi.com/article/1724245wpp/jin-ki-joo-is-an-optimistic-teacher-with-a-hidden-past-with-seo-kang-jun-in-undercover-high-school

"Adding to the intrigue, Soo Ah and Hae Seong share a hidden past that gradually unravels as the story progresses. Who will recognize the other first? What untold history connects them?"

I don't think there's any twin, that's too makjang for this type of drama. Also resembling can mean similarities in behaviour not just looks. "Who will recognise the other first?" This sentence clearly indicates they knew each other. 

I don't believe in a twin brother either. Soo Ah and Hae Seong  met when they were younger (First love). Hae Seong changed his name because he was bullied and dropped out of school so they didn't meet each other until now. But of course they don't remember each other after so many years apart.
I believe Soo Ah somewhere in episode 5-7 finds out that Hae Seong is undercover and together they investigate both the evil principal and all the ghost stories etc. In that way they come closer to each other for each day and feelings rise between them and then they finally figure out that they know each other from the past. But then Soo Ah remembers that she was hurt by him (don't know how) and they have an argument. Hmmm...well the rest...I will tell you later. :)) LOL