In brief, Ethel is right that truth is a defence to libel ( a defence called 'justification') However, it is still possible for a statement which is true to be defamatory and actionable if it bears innuendo.A little imagination will show that a statement of fact may be literally true but convey further meaning, a defamatory meaning, an innuendo, beyond itself.That hint, that meaning, might be from the context, the circumstances, the form of words used, its having special meaning or significance to the readers, or for other reasons.
It's the innuendo that was concerning here. The statement(s) might well carry an innuendo about people involved in the company, the more so if they are involved in the new enterprise. That's reinforced by Mustafa's point of the well known near fraudulent practice of successive businesses, as described. 'What a coincidence', thinks the world! Even a simple statement could carry that innuendo so the wise thing is not to make it.If you did, you'd be asked why and might find it hard to explain exactly what the motive was, if not a touch more than unnecessarily informing the public !
As to it not being a libel if you believe it true, well,in a sense that's an answer ( sometimes a defence) open to newspapers if they publish in ignorance of the defamatory nature and in certain other cases.They have to publish a prompt correction and apology and pay any costs,too. Sadly, it's not open to everyone to write that e.g the vicar was a paedophile, a thief and a fraud, who got his position by lying about his past ,and then blithely say "Well, I've a defence because I believed it"