Is there anything that you want from Japan? If there is, I'll go get it for you, so just let me know!
欲しいもの=something that you want
Let me know if there's something that you want!
欲しいものがあれば言ってね!
Is there anything that you want from Japan?
日本のもので何か欲しいものある?
anythingの代わりにsomethingでもOKです。
If there is, I'll go get it for you, so just let me know!
もしあれば買っていくからおしえてね!
ご参考になれば幸いです!