Many years ago, I heard the story of a man whose business partner did dirty. They were business partners for almost 5 years and the suddenly the business partner left with company's money. Even after several years, this man didn't recovered. He ended up sounding it as a warning to his kids never to go into business with anyone. The trust was destroyed and never recovered. This is just one of those sad stories.
He would have better educated his children to make the partnership legal by signing documents, providing collateral like guarantors that would indemnify the losses incase a party didn't fulfil obligation as stated in the document. This is what is obtainable in the modern world and not to go into partnership blindly with the hope of trust carrying the long time of the business. This is a mistake on his part and he has succeded to put such fear on his heirs. These days businesses are capital intensive and you need some level of partnership or support to succeed and whichever, whether financial support or partnership is better written in black and white, duties and obligations well spelt out
On the other hand, there are many success stories of friends who went into business together and succeeded to together. If you have ever gone into business with a friend, what were your biggest concerns and how did work through it.
Those who have succeeded have not only relied on trust but documentation of what the business is, its goals and all terms spelt out. It is a lesson and better to make legal document for businesses and not to only rely on trust.