Alien Spouse Become a U.S. Citizen after our Marriage?

Question:

I am a United States citizen, and want to marry a girl from another country. How could she become a U.S. citizen after our marriage?

Answer:

A foreign immigrant who marries a U.S. citizen must apply for U.S. permanent residence, or Green Card. This is a long process involving many forms and documents. After obtaining a Green Card, the alien spouse can apply for U.S. citizenship after three years as a permanent resident, if you are still marred and living together when the immigrant spouse. If not, the waiting period of U.S. citizenship changes to five years.

The alien spouse can also be refused entry of U.S. if she is found inadmissible, perhaps because of a medical problem, criminal history, past immigration violations, or the USCIS belief that your marriage is a fraud to get a Green Card.