(dailymail.co.uk) - Prince William bears all the hallmarks of a contented man. At 25, he clearly carries none of the emotional baggage that has dogged the life of his father, Prince Charles. From January, his military career will move on smoothly from the Army to the RAF, then the Royal Navy.
Plus, of course, his romance with Kate Middleton is on again.
The last bit is making those perennial worriers, the Royal Family's stiff-collared and often incompetent advisers, decidedly uneasy.
Despite the apparent rubber-stamping of Kate by the Prince of Wales, no one pretends to be absolutely sure in which direction this extraordinary relationship is ultimately heading.
There is real apprehension that should William dump Kate for a second time, the second in line to the throne risks being ridiculed, or even actively disliked, by the public for toying with her emotions.
For a young prince who could hold the future of the monarchy in his hands, this is no small matter.
Nor would this risk be mitigated by the belief, widely held in royal circles, that the comely Kate threw caution to the wind and inveigled her way back into the Prince's emotions. She, they insist now, is making all the running.
Kate's friends view things rather differently. They see a prince who was dreadfully missing the bright and personable young woman with whom he was virtually living after meeting her at St Andrews University nearly five years ago.
"The split was almost like a divorce, and just as painful, despite all the pretence of still going to parties and clubs," says one close figure.
"And I honestly think that, emotionally, it affected him more than her. She's stronger than he is."
During the weeks of their estrangement earlier this year, Kate's post-split nightclub sorties, her overt self-confidence and the flash of a large expanse of fishnet stocking - somehow exposed to the paparazzi as she laughingly stepped into a car with friends - all certainly grabbed William's attention.
Some of his friends saw his reaction to her behaviour during that period mirroring the way that his eyes "came out on stalks" the first time he saw her close up, as she sashayed down the catwalk in a diaphanous dress at a university charity fashion show.
One headline shrieked: "This Is What William Is Missing."
And clearly, despite bravado shows of masculine independence and the cry of "I'm free" as he jumped on a table at their favourite London nightclub Boujis (where else?), he was suddenly alone, surrounded by sycophants and missing her in his life and in his bed.
From there, it was one small and simple step for a future King to extend a princely courtesy to his ex-girlfriend by inviting her to join him and friends at the Wembley Stadium concert in memory of his mother; and, in turn, for her an equally simple courtesy to accept.
They may not have been side by side in the royal box at the concert, but that was it.
The split was healed.
Since August, they've been together again and getting closer all the time, as their two sets of parents look on.
No parental approval could surely be more pointed, nor more relaxed, than Charles and Camilla's invitation to William to take Kate for the weekend to Scotland to join them at Birkhall, the house on the Balmoral estate that Charles inherited from the Queen Mother.
And there, Kate was photographed being drawn even more deeply into the royal world of country pursuits by joining William stalking.
As yet, there do not appear to have been any matching weekend invitations from Kate's parents for William to visit their pleasant detached house in the village of Bucklebury, in Berkshire, although he has seen them socially.
During his time at Sandhurst, he regularly drove the 30 miles to have supper with them.
The couple, who run an internet business selling children's party goods (including toy princesses), took a disgraceful and totally undeserved battering from some of the classridden 'hooray Henrys' in William's circle last spring, but only after it emerged that Kate and William were no longer seeing each other.
Particularly offensive were the sneering taunts of "doors to manual" about Kate, in reference to her mother's former job as an air stewardess and her father once being a pilot.
It seems that these people, most of whom have thus far achieved little more in life than birth itself, didn't approve of the Middletons' middleclass genes and habits. Their juvenile braying certainly did the monarchy no favours.
Wisely, after what happened last time, the Middletons are proceeding with caution.
Even they are unable to predict with any certainty what the future holds for their elder daughter and her royal lover.
"They are pretending not to be involved with what is developing," says one of their neighbours.
"They're letting nature take its course."
Few will have forgotten that, last December, William pointedly - or so it seemed - invited Kate's parents to his passing-out Sovereign's Parade at Sandhurst.
The couple sat on either side of their daughter, alongside William's godfather, ex-King Constantine of Greece, and later chatted to the Queen. They looked for all the world like William's putative parents-in-law.
The couple had clearly been quite deliberately drawn into this important moment in the development of the future monarch. The arrival of the invitation from William, more than anything, was a potent indication that their daughter one day could be Queen.
William is known for his stubbornness, but he would never have dared invite them without the approval of the Queen, who would have understood its significance.
Indeed, she is very fond of Kate and comfortable with her unassuming manner, in much the way she enjoys being with Prince Edward's wife, Sophie, whose father worked for a tyre firm.
But in the wake of this highly significant family tableau at the Royal Military Academy, and just when it was assumed that 'Princess Kate' was a done deal, two things happened.
One was that Kate, inadvertently, may have over-played her hand.
So sure of William, she confided to friends of a possible imminent engagement announcement.
The other was that he suddenly got cold feet.
One of William's friends explained: "Suddenly, the enormity of what he was drifting into hit him - and hit him hard. It sort of woke him up to what was happening, and seemed to send him off the rails a bit."
This was the period when William was seen out partying and enjoying himself without Kate, and he allowed himself to be photographed with other girls.
William also confided his uncertainty to the Queen and Prince Philip. He wasn't sure that he "loved Kate enough".
The word "enough assumes real significance here, because he didn't say that he did not love Kate.
It was the degree of love he queried - rather poignant, coming from the son of a man who astonished the world by choosing the very day of his own engagement to Diana Spencer to pose the philosophical query: "Whatever love means...?"
When Kate learned of his uncertainty, her inevitable next step was to demand from William some kind of assurance about the future.
He couldn't give it. So they split.
Seeing them together now - or watching them, as fellow diners did, at Locanda Ottoemezzo, a popular neighbourhood restaurant in a quiet Kensington street just the other night - all that turmoil and uncertainty seems to be unreal, and very far away.
So is this the real thing? When William was not gently cradling her head in his hands, they were holding hands.
And this, remember, is a couple who have been sharing their lives for more than four years. Not a new love, then, but perhaps a love which, having been tested apart, has found a new intensity.
Is William certain now? It looks that way. But he is 25 and he has said, more than once, that he does not intend to marry before he is 30.
Presumably the next step will be for the couple to want to set up home together.
Edward and Sophie lived together (under the Queen's roof at Buckingham Palace), but for a future King to do so would require rather more thought and sensitive planning.
And don't underestimate the unique ability of most cackhanded royal advisers to mishandle matters.
Despite all the portents, William is still young enough to be revisited by an attack of cold feet. He may have his mother's looks and be a popular prince, but if another break-up occurred, millions of women would see it as a case of "like father, like son".
How ironic it would be if he ended up taking the same kind of flak that rained on Prince Charles over the way he treated Diana.
"Oh please, not that," murmurs one courtier.
"He must never be like his father."