Sheri Curts, Max's ex-fiancée with a failing family business, was the only person who knew Max's true identity.
That he wasn't Max Smith, but instead a member of the Stern family. A family with immense power and wealth, the kind that most people couldn't accumulate even across several lifetimes.
Despite all this, Aron had informed him that the only people aware of the current race to choose the next heir were the candidates themselves.
Of course, the heirs could tell anyone they wished about their inheritance or the Stern fortune, but Max was confident Sheri didn't know about any of that.
After all, Sheri had apparently left Max to chase after one of the other heirs, hoping she could secure some of their money to save her family business.
Max believed that the relationship between him and his ex-fiancée must have ended poorly. Otherwise, why wouldn't Max have helped her out financially?