Okay so the ending really leaves the reader to think and wreck their brain... but it's actually really interesting!! Basically what Jeah said at the hospital before Hana leaves is that there will still be Hana that will be born later in his timeline. If Hana manage to change the ending than what it's originally known by her in her timeline, that mean it's a success. Then, with the knowledge he have rn he can make changes in his timeline so the next Hana can do another different endings. They will keep changing the ending bit by bit. And of course, it will take a very long time but eventually there'll be a timeline where Jeah finally able to time travel to Hana timeline n they reunite n happy ever after (=・ω・=)
Okay so the ending really leaves the reader to think and wreck their brain... but it's actually really interesting!! Basically what Jeah said at the hospital before Hana leaves is that there will still be Hana that will be born later in his timeline. If Hana manage to change the ending than what it's originally known by her in her timeline, that mean it's a success. Then, with the knowledge he have rn he can make changes in his timeline so the next Hana can do another different endings. They will keep changing the ending bit by bit. And of course, it will take a very long time but eventually there'll be a timeline where Jeah finally able to time travel to Hana timeline n they reunite n happy ever after (=・ω・=)