THERE IS NO SUCH THING AS A DECLARATION FEE NECESSARY TO LEAVE GHANA. The Declaration fee is a fabrication made up by internet scammers because it fools their victims who are from other countries and usually don't know better.
Ghana's own Immigration
service warns outsiders not to fall for that here. You can see this on the FAQ of their website, which you can select from the bottom of the column on the left of their home page:
As you can see, Ghana does not require money to leave, and the US certainly doesn't require a foreigner to show money in order to enter the US. The US State Department warns of getting involved with a Ghanaian who is professing love to you online. They warn as well about the BTA and other "fees" to leave Ghana, because there are none. Our government's warning reads:
"Beware of anyone who requests funds for a BTA, or Basic Travel Allowance, as a requirement to depart another country for the United States. There is no such thing as a BTA. In other cases, your Internet friend will claim to need a travel allowance, or travel money, to be able to travel to the United States. Again, there is no such requirement under U.S. law"
Your online romance is a scammer. She has asked you for the one thing that even the Ghanaian government will agree makes her a fraud.
Don't send her the money. She won't be on the plane. She'll have an "emergency" such as an arrest at Customs or an accident en route to the airport for which you will be asked to pay even more money.
I know you'd like to believe her, but we have NEVER seen an online romance from Ghana be the real thing, once she asks for money. If you want harder evidence, however, feel free to upload any photographs and documents you have and I'll be happy to check them out.