GCG stands for “Green Card Girl.” That is the worst thing that can happen to you, and the hardest type of a scam to avoid. Her goal is to marry you and come to the US, so she will do her best to play the part of a happy loving girlfriend and then fiancée. These are the women who change overnight after their immigration paperwork is submitted. They have recently learned to file false Domestic Violence charges, in which case they are assigned a free lawyer and interpreter, get all kinds of help with the divorce, and their green card is practically guaranteed to them. Yes, despite the fact that their “marriage” has fallen apart, they will not be kicked out of the country.
In order to identify a scammer of this type you will need to learn and read much more than I am able to provide in this one article. Educate yourself as best as you can. Keep your eyes open. Don’t write everything off as cultural differences. If you are suspicious, check things out; there are different resources for that.
I will say in conclusion that while finding a decent Russian woman can be very rewarding, the process of searching has been rightfully called swimming with sharks. Now that you know what those sharks are, you are better prepared to deal with them – if you still wish to go that route.