WHY CAN'T WE LOVE SOMEONE TO CHANGE THEM FROM LEAVING

 WHY CAN'T WE LOVE SOMEONE TO CHANGE THEM FROM  LEAVING

1. We basically met through a mutual friend online and played chess after that she had messaged me which I replied after weeks. She then saw my profile on social media and having a few things in common such as going to the gym, we started talking a lot. Her giving me a lot of energy and starting conversations. After that invited her to meet and we met and she was really pretty. We talked and even sat beside each other. After that i took her out on a date and even visited her house where we smoked in the terrace. She even game me her hoodie and i cherish it till now. After then i gave her mine and also gave her a bouquet of roses when we met.
2. We went to Korean restaurants and had soju and her chugging the whole bottle and I had to take her as she held onto my arm. We went to karaoke and had tons of fun together we even exchanged hoodies and I saw her keeping the flowers I gave her in a vase, but gradually it started to change as she is now worried for colleges and is going back to japan but even if she is busy she doesn't reply back when she isn't and even if she does she replies very dry. It maybe just me who fell hard for her as when we got into a relationship and had our first kiss she messaged me saying she wanted to make the relationship casual. My brother says that my relationship right now portrays the movie "500 DAYS OF SUMMER" which is quite true in most of the parts. You cant always say the right things, sing the right songs or love enough for the person to stay. I don't have much going on my life as I take a lot of things easy but I though when she came in it will give my life meaning and i was committed to her. She is really pretty and intelligent so many guys will fall for her but they wont see her the way that i do. It is inevitable that we are going to break up before she goes to japan as she doesn't do long distance and i cant really open up because she isn't open about her feeling I tend to shut myself off to tell her stuff. I don't know what I should do with her and I also cant blame anyone but the times as we are going into the big world and she wants to try different things and become someone.