How to advise or help my friend who won't listen.?

She told me she is going to get a $200,000 grant, and an FBI agent is going to bring it to her. They started texting and talking, and she said he wants to marry her, and now something that sounds totally off the wall, is that she says the President is now involved, she can't believe this is happening to her, won't tell me why the President is involved, or anything about it, only that she can't tell me, and she is totally elated, and Very excited. This sounds to me like a total scam, and I'm afraid she is going to be hurt badly. When I try to get her to consider this guy is lying, she shuts me down. She said he told her his badge number, but she will not check him out. She says she trusts him and wouldn't do that. This has all come about within this month. Oh, and she said she had to pay all the taxes on the $200,000 before it could be released to her. She wouldn't tell me how much, but that she did pay it. She will not listen to reason, and would shut me out if I persist. I have no clue as to how to help her. She did tell me the name of the man. I cannot find anything about him online. Advice is welcome.