If you want, you could come to Japan and live with me.
Moving to another country is a big decision so by saying "If you want," it shows that you would like for him to but that he is able to make the decision on his own. You can use this both in American and British English. I hope that this helps :)
他の国に引っ越すというのは大変な決断です。ですから、"if you want (もし良かったら)" と言うと、「来てもらいたいけど自分で判断して良い」という意味になります。
アメリカ英語でもイギリス英語でもこの文章は使うことができます。
お役に立てると嬉しいです。
Any of these sentences can be used :-
1. You should come to Japan and live with me.
あなたは日本に来て私と一緒に暮らすべきです。
2. Come live with me in Japan.
日本に来て私と一緒に暮らして。
これらどちらの文も使うことができます：
1. You should come to Japan and live with me.
あなたは日本に来て私と一緒に暮らすべきです。
2. Come live with me in Japan.
日本に来て私と一緒に暮らして。
If you come to Japan. I will let you stay in my apartment
You could say,
"You should come to Japan. You could live with me!"
You are telling the person which country they should go to and then explaining that the person could live with you. You are offering them a place to stay.
Another way to say this is,
"If you come to Japan. I will let you stay in my apartment."
Here you are offering to let them stay with you if they come to Japan.
This is a conditional sentence. If they do something (Come to Japan) you will do something (Allow them to stay in your apartment.)
次のように言えます。
"You should come to Japan. You could live with me!"（日本に来た方がいいです、私と一緒に暮らせます）
「日本に来た方がいいです、私と一緒に暮らせます」という意味です。滞在場所を提供しています。
次のように言うこともできます。
"If you come to Japan. I will let you stay in my apartment."（日本に来たら私のアパートで暮らせます）
ここでは、「日本に来たら私と一緒に暮らせる」と提案しています。
これは条件文です。「あなたが A（日本に来る）をすれば、私は B（アパートに住ませる）をする」。
"Do you want to live with me in Japan?" is a question, while "Come to Japan, we could live together!" is a suggestion. Both are letting the other person know that you would like them to come to Japan and you would like to live together and both are polite ways of expressing that.
"Do you want to live with me in Japan?"（日本で一緒に暮らしませんか）は、質問です。
一方、"Come to Japan, we could live together!"（日本に来てください、一緒に暮らしましょう）は、提案です。
どちらも、日本に来て一緒に暮らして欲しいことを丁寧に伝えています。
If your significant other is having a difficult life currently and you wanted to help him, by telling him he can come to live with you in Japan, you could say any of the following: "You should come and live with me in Japan", "Do you want to live with me in Japan?" or "You could come live with me in Japan". All three of these express that you would like him to move to be with you to help him.
生活状況が困難な恋人に日本に来て一緒に住んではどうかと提案したいなら、次のように言えます。
"You should come and live with me in Japan"（日本に来て私と一緒に暮らしましょう）
"Do you want to live with me in Japan?"（日本に来て一緒に暮らさない？）
"You could come live with me in Japan"（日本に来て一緒に暮らさない？）
上記三つの文は、自分の家に住まわせることで相手を助けたいことを表します。
By saying: "You could come and live here with me!" you are suggesting to the other person that it is an option for them to live with you where you are. You could also say: "You are welcome to stay with me in Japan." which is a polite way of letting the person know that they are welcome to stay with you- it is more of an offer than a direct suggestion.
I hope this helps! :)
"You could come and live here with me!"（日本に来て一緒に住みませんか）
これは、日本に来て一緒に住むのはどうかと提案しています。
次のように言うこともできます。
"You are welcome to stay with me in Japan."（日本で一緒に住んでもいいよ）
「日本で一緒に住んでもいいよ」と伝える丁寧な言い方です。これは直接的な提案というよりは申し出です。
参考になれば幸いです！
アメリカ合衆国 
カナダ 
日本 
イギリス 
