My bro has a Viet gf too, & like you, they hav communication
barriers. And like u too, they are separated by two
different places.
....
Love concurs all barriers! I believe u are onli havin some
doubts abt marriage, cos afterall, u r so used to sleeping
alone! U need to do somethin to reassure urself tat
everything is gonna be fine if you are 100% sure tat she is THE
ONE. 
Kudos to your brother. I hope as much as you do that a happy ending
lies ahead.
