The woman who says William Kennedy Smith raped her told police she had a harrowing night in which she was overpowered, assaulted, cursed and told that no one would believe her if she cried rape.

According to a graphic, detailed affidavit authorities released Thursday, the 29-year-old woman said she ran from Smith, but he tackled her.When she tried to push him away, she said he pinned her down, "slamming his chest" against her. At one point, she told police, he yelled "Stop it, bitch," when she continued to struggle. Later, she said, he told her no one would believe her if she said he raped her.

Smith, the 30-year-old nephew of Sen. Edward M. Kennedy, was charged Thursday with one count of sexual battery and one count of battery. Rape is classified as sexual battery in Florida.

Smith, who has maintained he is not guilty, says he is worried and saddened but expects to be exonerated in court.

Smith, his famous family rallying to his defense, is preparing for his trip to Palm Beach, Fla., to be fingerprinted, photographed and booked on the charges.

"I didn't commit an offense of any kind," insisted the 30-year-old nephew of Sen. Edward M. Kennedy, D-Mass. Smith spoke briefly to reporters Thursday when he appeared at the offices of his lawyers shortly after Palm Beach police issued a warrant for his arrest.

Both Edward Kennedy and his son, Patrick, a Rhode Island state legislator, said they are confident Smith is innocent. The two Kennedys were at the family compound in Palm Beach on Easter weekend when the alleged assault occurred on the beach behind the house.

Smith, who is less than three weeks from completing his final year of medical school at Georgetown University, conceded, "I'm worried about my family and obviously my future."

Palm Beach Police Chief Joseph Terlizzese said Smith's attorneys "intend to surrender their client to the Palm Beach Police Department early next week."

The woman's lawyer, David Roth, says his client felt relieved and vindicated.

The woman said in a statement that had she known she would be identified publicly she might not have gone through with the case. The supermarket tabloid The Globe, NBC News, The New York Times and other media identified her by name. Misdemeanor charges have been filed against The Globe, and authorities said charges against The Times and NBC are being considered.

"Had I known my name would be released, it might have dissuaded me from going through with this," the woman said. "Rape needs to be reported to keep others from going through what I went through."