Jerome Bonaparte used brief words to directly shut down all of Cavour's remarks that could be detrimental to the Kingdom of the Two Sicilies. Since his own boss regarded the Kingdom of the Two Sicilies as a harmless country, what reason did he have to prevent his boss from continuing to recruit followers?
Cavour certainly couldn't simply make unfounded claims against the Kingdom of the Two Sicilies, insinuating they had ulterior motives!
Now, the only thing Cavour could do was to leave a good impression on Jerome Bonaparte, striving to have Jerome Bonaparte lean as much as possible towards them.