Ok, LDR once again.
In your situations, it's very difficult to see much future in your
relationship because the odds are terribly overwhelming. You can
only know if this relationship if for you ONLY after you have lived
together for a period of time. Love is great, feeling is strong -
but we must not let that influence and blind us to our risky
future. You have to anticipate problems way before it arrivals and
hits you in the face because your relationship is so
fragile - you need to shield them from the hostile wind
and build up a steady foundation before you expose them to
'experience'.
You can attempt this relationship and your objective of this move
has to be: Minimize possible risk. Culture difference can be
respected and learned, but as for language, it's truely a feat on
the strength of your relationship. There are some 5 pointers that
you have to have before you can consider this relationship:
I) I hope financially, you are independent and no problem with that
because if that wasn't the case, I advise you to drop this
relationship. Too much problems thrown in a relationship can
instantly kill it before you can find ways to salvage. 
II) Mentally and emotionally you have to be 10 times
more understanding and stronger. Temper has to be curb.
Empathy place with intiative and decision making. Your mind and
heart must be prepared and trained to see that this relationship
WILL NOT be a smooth going one (like all true love). Rewards in
this relationship can only be felt AFTER you spend
mutual effort in maintaining and upkeeping this relationship.
III) You have little choice; to understand culture, you have to
begin by studying their language. You can go to my ex-school
(www.ikoma.com.sg) Lack of
communication or mis-communication are the top killers in
relationship. See, when you wrote an email to her saying that this
relationship may be a little difficult and everything, she became
defensive and blasted back at you. THIS IS MIS-COMMUNICATION.
Imagine if you were to have real life issues with her but you can't
find a common ground to talk things out... this could mean certain
death. You may want to say something, but she interpret them
differently or vica vista.
IV) An immediate jump to marriage is a no-no. I suggest if a title
is critical, get engaged instead. In this way she
could stay over for 3 - 6 months to get use to the life in here
WITHOUT people talking. If you are taking foreign language class in
say, Ikoma - there are many Japanese people there. At least when
you can taking the class and she waiting for you to finish, she
will get to know people of her own country - this minimize home
sickness and establish networking. 
V) There is no room for 'what-if' WHEN YOU HAVE DECIDE TO
PURSUE this relationship after considering Phrase I
and II - be positive and ALWAYS employ the 'right' way to handle
your own relationship. Drop previous bad habit (e.g. Break-patch,
cold war, violence if applicable, etc). Both of you must share this
common vision in your relationship before you can move to greater
heights. Constantly encourage one another or even
do little things to make the day happier.
Personal: If I had my chance of
that LDR... the yunhaier today would be so much
different.......
Cheers