You really do not understand this even with multiple long time respected posters trying to help you.
The AP is as strenuous as it gets on confirming and collaborating information. It's why Withers is rarely first with Cavs news(and often doesn't chime in at all), but when he does, it is to be trusted.
Secondly: Woj/Shams/the Vertical. They are THE definitive and most trust worthy source of breaking basketball news for the past almost ten years. In the past five years, given HUNDREDS of breakin trades and signings, you can count the info they got wrong on one hand.
One of the main reasons for this is that they have longstanding relationships with almost all the agents and FOs of the league as well as sources within the league office themselves. All trades and signings must be submitted to the league first and Woj has sources their who will tip him off when the paperwork(digital nowadays) has come through.
In short, while there is a lot of info out there to be skeptical of, but Cavs info coming from Withers at the AP or any NBA info coming from WOJ/Shams/TheVertical is correct 99.99 percent of the time.
Continuing to be stubborn about it demonstrates a complete lack of understanding of the nature of the NBA over the past decade.