There is a school of thought that says you can tell a lot about a person by the car they drive.

Diane Foreman drives a Maserati, but the fact that this is worth even mentioning probably says more about the lack of successful businesswomen in this country than it does about her personal style.

She used to drive an Aston Martin, but passed that on to broadcaster and former boyfriend Paul Henry. Needless to say, it's since found another home.

Her taste in cars and men aside, she comes across as a thoroughly nice person who, if anything, is a little too open and honest, perhaps even a little naive.

But behind the charming exterior is a woman of steel, say her friends - and foes.

"She is one tough cookie - don't be fooled by her size," says business partner Carmen Bailey, who together with Foreman owns the recruitment agency Emergent. "She is one person I wouldn't want to have a legal battle with."

In fact, the only high-profile legal battle she has been involved in was over the Foreman family trust. Her marriage to wealthy businessman Bill Foreman, who is significantly older than her, caused all sorts of ructions, including accusations from Bill's children from his previous marriage that she was a gold-digger. The squabble was eventually settled out of court.

She and Bill, now 83, split a few years ago but she insists that they remain good friends.

There were, of course, the allegations of an affair with former National Party leader and Reserve Bank Governor Don Brash. The resulting publicity was particularly tough on her kids, Foreman admits.

These days she is enjoying the company of farmer and economist Jason Smith, the nephew of Parliament's Speaker, Lockwood Smith. Lockwood's wife Alex Lang is one of Foreman's best friends.

She volunteers, with a wry grin, that she is enjoying being with someone who is "very settled".

Foreman's involvement with the National Party has been well documented. According to Nicky Hager's book The Hollow Men, she was one of the key figures who recommended a "no Brash, no cash" policy to persuade the Nats to back Brash as leader.

Exactly who leaked Brash's emails is a mystery that has not yet been publicly solved. But after Foreman's home was burgled - not once, but twice, just before the 2005 election - she even hinted at a Watergate-style conspiracy, muttering that she believed the culprits were "closer to home" than some people were suggesting.

While she is hardly a regular in the social pages, she did recently feature on the cover of Simply You Living, showing off some gorgeous clothes and her newly refurbished Remuera home.

And in June she gave an interview to the Herald on Sunday, saying she wanted to put the record straight after years of "hurtful", "untrue" and "embarrassing" stories.

Another friend believes the fact that Foreman was adopted has affected her deeply. However it didn't deter her from adopting two of her own children.

Her 18-year-old adopted son Josh is half-Samoan. When he was eight months old she discovered that he was deaf and he subsequently became an early recipient of cochlear implants, which were controversial at the time.

Almost everyone agrees she can be a very caring and compassionate person, generous to a fault. But there are inevitably some people who have dealt with her in the past whose eyes roll at the mention of her name.

"She is a very complicated individual, and she can be a very difficult person to work with," says one former colleague.

Kirsty Reynolds, who once owned a fancy shoe company with Foreman called Reynolds & Young, would only say the experience had been "valuable" and "educational".

The company has since been restructured and Reynolds stresses that Foreman was "completely honourable" in all her business dealings with her.

Foreman admits the partnership was a disaster and says the mistake she made was buying into the company simply because she loved its products.

"That was when I was young and that was a really interesting experience for me. It's a great example of me seeing myself as a target market of one."

But she is annoyed by the other suggestion that she can be difficult to work with. She points out that she has only ever had two PAs, and all her senior managers across her various businesses have worked for her for many years.

"One of the things I am most proud about is my low senior management turnover. If I was such a difficult person to work for, I wouldn't have such a loyal team."

On the other hand, she admits her brief tenure two years ago on the board of listed juice company Charlie's had its difficult moments.

Chairman Ted van Arkel was reluctant to comment, but it is understood she was at loggerheads with the rest of the board over their desire to hire someone she had previously fired. Foreman confirms it, and says the experience taught her that she is not suited to public companies.

"Charlie's is a great little business, but I'm not a public company person. I need to be able to have my hands on the steering wheel. It was a great learning experience... and the learning for me was that I am better doing my own thing. I'm too much of a control freak."

A former colleague couldn't agree more, and says he was surprised when he heard she was in the running for Entrepreneur of the Year.

"She's got the best intentions, but she's no entrepreneur," he insists. "She's got a chunk of money and she throws money at things, but at the end of the day they are things that other people have created for her. And her strategy is all over the place - it's all driven by emotion."

The same person believes former chief executive Stewart Alexander (who died of cancer this year) and current managing director Shane Lamont do not get enough credit for the success of Emerald Foods.

In fact, Foreman is quick to praise her managers for their talents, and Lamont himself seems genuinely grateful for the opportunity.

"I can't say enough about Diane. She's been an absolute mentor and made sure that not only the business improves but that I improve too, so I'm very happy."

And she is clearly stung by the criticism. "I find that really annoying. If you look at all the previous entrepreneurs [of the year] they've either come into family businesses and done better with them, or started their own businesses. If you look at what I actually do, I've taken failing businesses that big companies like Nestle couldn't make work, and I've picked those businesses up and run with them and turned them into highly profitable, successful exporting organisations, and I think that's quite entrepreneurial," she retorts.

"And I think taking a blank sheet of paper with four other high net worth individuals and creating something that wasn't there, with MercyAscot - that's pretty entrepreneurial."

She also points out that it would have been easy to take the cash from the sale of Trigon and live off the interest for the rest of her life. "I'm really sensitive about that, because that's basically saying my work has been for nothing, and I find that horrific because it can't be true."

Interestingly, Foreman's own mentors include businesspeople with very different world views, such as David Levene and Rob McLeod. She is also quick to acknowledge Bill's enormous influence. But she admits she gets sick of people assuming she has no brains of her own.

Foreman has made no secret of the fact that she left school at 15, and can't help noticing that the public seems to lap up the street smarts of entrepreneurs such as Graeme Hart and Peter Leitch.

When it comes to women in the same position, it seems to be more a case of "where's your MBA, love?".

Bailey believes some of the sniping about Foreman's style is simply sexism, and agrees that some people probably underestimate her. "I think it's because she happens to be blonde and petite."

One of Foreman's best traits is her enormous energy and enthusiasm, says Bailey. "And the thing she cares most about is the customer."

While she is quick to praise, and to criticise, she doesn't hold grudges, says Bailey.

Almost everyone acknowledges she is extremely driven, and Bailey believes it is Foreman's determination not to be poor and single again that keeps her so focussed.

"I think it comes from being a solo mother, to be honest. It's that 'I'm never going to go back there' feeling, and that enormous inner strength."