If you tell yourself it’s easy, you’ll find (a way to make) it easy. If you tell yourself otherwise, that’s also what you’re likely to get. As motivational speaker Les Brown is fond of saying: “Thou shalt also decree a thing, and it shall be established unto thee”.
Self-fulfilling prophecy. It is what you say it is.
Japanese is easy. Getting used to Japanese is easy. Say it. Feel it. Believe it. Experience it. Enjoy it.