Which of the six languages is easier to learn, Japanese, Korean, French, Russian, German or Thai? Easy to remember? There is a lot of room for future development. ...

The natural and easy part is Japanese, because Japanese is the evolution of Chinese. Even if you don't know Japanese at all now, you can still understand it when you go to Japan, because Chinese characters are easier to learn. If you learn Japanese well, you can work in Japan. If you take the Japanese Certificate II or something, it will be easier to go to work.