Jin's attempts at saving his friends from their fate will only work when he learns to love himself and encourages them to love themselves as well.
The reason everything keeps going wrong for the boys no matter how many times Jin time travels/dimension hops is that he's only been changing the course of events (getting Jungkook to save Yoongi from the fire, stopping V from killing his father, etc.) without addressing the underlying issues they all have that keeps leading them into their self-destructive behavior in the first place. Only when they learn to accept themselves will they be saved from their fate. The girls symbolically represent a version of the boys they are paired up with, and their courtships represent the boys learning to "love themselves".
At least some of the girls are shown to be Foils of the boys they're with:- One being a musician like Yoongi and becoming someone he relies on by taking care of him, as well as possibly going out of her way to find Jungkook for him.
- Another being a Delinquent like Taehyung, with Taehyung taking on Namjoon's role and replicating his behavior towards her, taking responsibility in her place by allowing her to escape from the police by letting them catch him.
- Another one being a dancer like Jimin and Hoseok, and also being Hoseok's Childhood Friend.
- Another being a hospital patient like Jungkook, and stopping him from acting irrationally (in a Red Oni, Blue Oni sort-of way). She also indirectly makes him realize how much about himself has been actually defined by his hyungs and his admiration for them.
- Another one seems to care about activism, but never actively interacts with Namjoon - making him constantly agonize on whether to talk to her or not.
- The last one doesn't seem to get much characterization, but has an interest on the Smeraldo Flower - with Jin going to great lengths to get in order to make her happy and for Jin to become a good person in his eyes.
Alternatively (or complementary to the point above), they're not necessarily actual pairings, and they're there to instigate their Character Development.
None of the characters' relationships with the girls succeeds, even platonically - they all end up leaving, or being pushed away, or in one case, dying before they get to talk. It's unclear if all of the boys show romantic interest in them, as well. As seen in the point above, they are key for the boys realizing things about themselves and push themselves in the right direction - either leaving when their role is done or instigating change by their departure. Jin has messed with the timestream/dimensions so much that the other boys are starting to notice the shifts happening.
The Notes have revealed at least a couple of instances of the boys getting a Flash Sideways in the form of nightmares, with Jungkook dreaming about Yoongi on a bed while the room is on fire, like the scene in "I NEED U" while on a fever, and Taehyung having constant nightmares about Yoongi dying, Jungkook getting into a car accident and Namjoon getting into a fight. Yoongi is also mentioned to have a feeling of Déjà Vu at one point. Following the above, those who are noticing these shifts the most are the ones who were most affected by them and Jin's actions, but are also key in changing others' fates.
The ones who seem to have more awareness other than Jin are, in increasing order, Yoongi (who has feelings of Déjà Vu), Jungkook (who has a Flash Sideways nightmare while on a fever) and Taehyung (who has constant nightmares + has strange demeanor at the end of "Euphoria"), with the latter two's Flash Sideways involving Jungkook, Yoongi and (in Taehyung's dreams) Namjoon. There seems to be a pattern.However, the reason can't just be that the ones who gain awareness are the ones who die, in which case Yoongi (who arguably gets the worst death and is said to outright die in Tae's nightmares) should have more awareness than the others. While it could be a factor, there should be more reasons.
What we know about the three:
- Yoongi: Due to Jin's mistake, he ends up fighting back against a teacher to defend Jungkook and gets expelled. After that, he throws away the piano key of his old house in rage and refuses to play the piano anymore. In one of the timelines, he sets his room on fire, with 2 different outcomes: he dies in the fire, or Jungkook comes in time to rescue him. He's very affected by Jungkook's car accident and goes through a HBSOD. Another Note shows him reuniting with Jungkook in a music shop, with Yoongi feeling that the event was something he had repeated many times before, and that he had forgotten something important. He also happens to be there to help Jimin to face the arboretum again in another Note.
- Jungkook: Also due to Jin's mistake, he's left completely alone after the group separates. We see him going through a Despair Event Horizon in different timelines; in one, he contemplates throwing himself off a building - with one of the outcomes being that he stops after he gets a phone call from Yoongi; in another, there's the events of "I NEED U", where he lets himself get beat up by strangers and gets hit by a car, being visited by the Mysterious Figure. In another timeline - in which he has his nightmare -, he visits Namjoon to learn how to become an adult.
- Taehyung: Partially learns about the incidents that led to Yoongi getting expelled, and develops resentment towards Jin, believing the older sold them out - one of the first Notes shows a scene of the two getting into a fight after Taehyung reveals something to the group, leading to the group breaking apart. In one of the timelines, Tae murders his father in "I NEED U", leading to the events of "Prologue", where he presumably kills himself - or attempts to - during the boys' trip to the beach; in another ("Euphoria"), Hoseok stops him at the last minute, allowing his father to get away, and hangs out with him after. One unclear timeline shows him with Namjoon, in which he has the constant nightmares.
Therefore, it could be said that the ones who gain the most awareness are the ones who both are affected the most by Jin's actions and have a bigger effect on the others throughout the timelines. Jungkook - being a more passive character who just wants to keep his friends nearby - is very affected by what happens to the others, and Yoongi - who goes to extremes to stay out of everyone's way in the worse timelines - has a big effect on what happens to other people; Jungkook and Yoongi's fates (whether they live or die, in particular) also happen to be inextricably linked to each other, with the death of one only being directly prevented by the other, or (in Jungkook's case) the Mysterious Figure. Meanwhile, Taehyung's actions seem to particularly affect the lives and dynamic of the group (and his family's, as well) while also affecting Taehyung himself the most.
Jin is a Time Lord.
Jin is implied to have the power of Time Travel. The fact that there's a phone cabin that appears prominently in the series might well be Jin having a similar TARDIS to the Doctor's. Namjoon being unable to enter the cabin in "Reflection"? Jin. In the events after The Most Beautiful Moment In Life: The Notes 1, Jungkook will now be able to remember the loops or gain some sort of awareness.
The accident that sent Jungkook to the hospital also led to his apparent Deal with the Devil. The mysterious figure tells him "Living will be more painful than dying, do you still want to live?". This could mean that after the loop we follow in the novel, Jungkook might now get a similar ability as Seokjin, Taehyung, or something in between that will give him some degree of awareness of the "Groundhog Day" Loop or a tool to help Seokjin's quest. After all, Seokjin was told at the very beginning that he could not be able to do this alone.Alternatively, Jungkook's awareness might turn him against Seokjin (and he kind of already has) due to his (implied) memory of Seokjin being involved in the accident.- It's also worth noting that the song "Jamais Vu", which is explicitly about the main plot of the story, is sung by Jin, Jungkook, and j-hope (aka. Hoseok). In SAVE ME, 3 chapters are focused on Hoseok becoming suspicious and distrustful of Seokjin after noticing Seokjin knows things will happen before they do.
Eventually, Seokjin will have to ask for the help of one or more of the other boys to break the cycle, leading to the Note so far only released in LOVE YOURSELF: Answer.
This will be Taehyung (due to his dreams), Jungkook (see above), Namjoon, or everyone. This will also require that Seokjin is absolutely honest with them, for better or worse, which will also fit with the themes of the LOVE YOURSELF series.In Jungkook's case, this will be complicated by the fact that, in the novel, Jungkook is implied to remember Seokjin being involved in the car accident, and already acts tense around Seokjin afterwards.