There really is no risk for you. You are not going to lose your citizenship or go to jail. The risk is all for the person since they can get deported.
Penalties for participating could include perjury. Participation in a marriage fraud can result in up to five years in prison and/or up to $250,000 in fines per count. You take a huge risk. And just because you're not caught in the beginning doesn't mean you can't be later on a visit or stokes interview or whatnot.
Yes, marrying a U.S. Citizen in order to become a U.S. citizen is illegal.
Marrying a citizen is not enough to get citizenship. If the marriage was done to get citizenship and there was no love or committment, the marriage is illegal.
NO. It is not a criminal act.
It is wrong for a citizen to knowingly marry an illegal alien. Get advice from an Immigration lawyer.
Can an illegal alien who was deported and barred for ten years come back sooner by marrying an us citizen?
No you should be deported
No, an illegal alien does not become a citizen upon marrying a US citizen. You have to wait a period of time before you can start the process of becoming a citizen. Once you have completed your waiting period you must file petitions to become a citizen and go through citizenship classes. You then take written or oral exams.