The way developer Jody Sherman tells it, her idea for what are the most expensive condominiums in the United States had its root in fear. It's no longer easy to be rich in a Beverly Hills or Bel Air, Sherman says. Rising crime rates and increasing servant troubles have made the mansion life very hard.

So Sherman, who lives in a mansion herself, decided that what Los Angeles needed was a safe condominium building that would provide all the space of a mansion with none of the aggravation. Her idea -- Wilshire House -- is being turned into 67 condominiums priced from $750,000 to $7 million.

Inflation, however, is everywhere. The cheapest condo in Wilshire House now is $1.5 million and the two penthouses would have been a bargain a year ago at $7 million because now they are priced at $11 million.

Fortunately for Sherman, her customers don't seem to mind the inflationary spiral.

"My costs have gone up, so have my prices," the developer said gently. She nodded as her public relations aide, Jackie Applebaum, explained in an interview that, "I don't think that price is an object for these people. What difference does $200,000 or $300,000 make? If you're going to pay $1.2 million, it's not much different to pay $1.6 million."

Crime has made life frightening for the wealthy, she says. Sherman can't even give away two Rolls Royces as she wanted to. It was her thought that the buyers of the two penthouses should each be given a Rolls with personalized license plates as the Wilshire House way of saying "welcome."

The trouble is, her customers don't want the cars. For one thing, they've all got Rolls Royces, Sherman said. More importantly, however, the Wilshire House sort of people are trading down in an effort to become less conspicuous, she added.

"People follow your Rolls home from a restaurant. They're robbing people in their cars. The Rolls owners are sitting ducks," she said.

If Sherman is right, the fortress atmosphere of Wilshire House is America's future. She insists, "I think it's the way of life from now on. I think it's the only way to go."

Sherman was one of her own early customers, buying half of the 20th floor, because of her fears over security. The other half of her floor was sold, to a buyer who wanted a $7 million penthouse and arrived too late, Sherman said, shaking her head at the way the ball bounces. By the time the customer got there, $7 million bought half of the 20th floor, not one of the penthouses a flight higher up.

In addition to 24-hour-guards, elevators keyed to stop only at one floor per trip and a window-and-door alarm system so elaborate that as any guest (or potential thief) is announced from the building entrance, the resident can see him or her without leaving an apartment.

So far, she has sold 52 units. The other 15 remain on the market, but with the building not scheduled to be completed until March 1982, Sherman doesn't seem likely to come up short of buyers.

She has 30-year financing for her condos with a Los Angeles bank, but so far none of her customers has been interested in using it. Sherman explained, "They've all paid cash."

Sherman says the buyers are just who she thought they would be -- lawyers, doctors corporate executives, and entertainers. All are Americans, overwhelmingly people who have just sold a mansion nearby and want a safer, less aggravating existence.("Help is hard, you know," Sherman said.)

At Wilshire House many services will be included in the average $1,000-a-month maintenance cost each condo owner will be paying. Daily main service, pet walking, a personal shopper or "automobile grooming," will be available at extra cost.