[look even he's not dumb enough to interrogate not-Dio.]

It leaves us at 'we should keep an eye on things in case I'm wrong'. Don't panic, but wait and see how things unfold, right?

[...]

Jotaro, I wouldn't take any course of action if I had even the slightest reasonable suspicion that it would get one of you hurt. You know that. I don't trust Diego and I have no idea what to make of him, but I'm confident he isn't an immediate threat.

I only thought it was better for you to hear about him from me instead of finding out for yourself.