"I'm out of money," love-struck Keith Ruff declared yesterday.

Three weeks ago, the ex-stockbroker from Beverly Hills came to Washington to persuade his former girlfriend, 20-year-old Karine Bolstein, to marry him. After spending an estimated $20,000 on flowers, catered food, magicians, clowns, clothes, limousines, a hired Learjet, toys for her younger brother, liquor and cigars for her father and running up a $3,700 bill at the Washington Hilton, Ruff feels "a lot of hurt" after his costly courtship failed to change her mind.

Ruff and Bolstein met each other last July at the Tysons Corner shoe store where the woman worked. They began dating, but when Ruff pressed for a trip down the aisle, Bolstein bolted.

"I'm 20 years old," she said at the start of Ruff's Cupid campaign last month. "I'm not in the mood to get married."

Ruff, who claimed to be unemployed and independently wealthy, said at the time that he would continue showering the young cocktail waitress with presents. He would not give up, he said, until Bolstein said yes or his bank account said no.

To prove the "purity" of his intentions, the heartbroken Ruff said yesterday, he turned down several opportunities to take his case to the airwaves after his story first appeared in The Washington Post. The offers came from "Good Morning America," Playboy Cable TV, Cable News Network, "PM Magazine" and local television and radio shows. Ruff's mother also said she received letters and photographs of young women, eager to marry her free-spending son.

But Ruff is still ready, although he says he's down to his last pennies. "This is not puppy love," he said dejectedly. "I've never had feelings like this before. I made a promise to her that she was the only woman I would ever love." Ever the romantic, he was hoping to tie the knot on Valentine's Day. But it doesn't seem likely. "I don't love him," Karine Bolstein insisted.

Bolstein's father, an attorney with the Labor Department, seemed relieved yesterday to hear the siege was over. "I feel sorry for him," said Arthur Bolstein. Because of the barrage of media attention, including calls from West Germany, the Bolsteins were forced to get an unlisted phone number.

As for the rejected Romeo, he says he plans to fly to France on his last credit card. "I'll send her flowers whenever I can," he said sadly. "I really love her."