If I have a good business idea wich is probably no way to 
protect it as a patent but still can worth a lot to those who implement it.
Is it possible to sell the idea and guaranty that those who get the
idea won't deny the deal?
is there anyone who specialize in such cases ?
for example there is the story about someone who suggested a
toothpaste company to increase their profits by increasing the hole.
I don't know if this is just a story or not but is it possible for
somthing like that to happen in reality ?
I gave this example because obviously this is not a patent , just a good idea.

I know of another old and probably apocryphal story.

A guy approached a match manufacturer and told him a way to save money
- it was by just having one striking surface rather than two
- supposedly he was paid for it ... maybe ...

Another that is real, but nobody got paid for it.
A European soft drinks manufacturer had red and black printing on
their bottle caps.
- elimininating the red saved a fortune - and was an aesthetic improvement.

If you get a chance, dig out the short story by H. H. Monroe (Saki)
about the 'Mouse that helped the Lion'

Good Luck - but my instinct is that you need to approach this problem 'sideways'

And there is a real problem, if you cannot protect your idea, the
company can just use it; you are dependent upon management's sense of
ethics.  Higher Mgmt may be better on that, having the funds, than
someone down the line who could just boosts your idea as his own ... 
IF you are an employee, there may be a suggestions award system. Maybe
you could make a contract with an employee for a healthy share of such
an award and let him present the idea, but that is just a maybe ...
Is that approaching the problem "sideways"?

I had the satisfaction of getting a suggestion implemented that didn't
cost much, and only saved me (pipe smoker) from spilling matches: 
that the producer not use the same imprint on both sides of their
matchboxes.  Oh, a girl called, and maybe I could have asked for
something more, but just asked for a packet of ten of the new
matchboxes and received them eventually.

In this day and age, it is very safe to have a notarized, dated letter
before you approach the company.  They know they'll be sued if they
even think about trying to rip you off.  I think you're completely
safe if you're documented.