To Know Death / To Know About death.

[Strazio Rockwell]

I'd agree with Carmelita.

In common speech I'd also argue that it means more in context of what is being said and both are likely said with the same intention.

In the nitty gritty side the first one inplies that the speaker has experienced death whereas the latter has spoken with someone that has experienced death or has been near death enough to be familiar with it. Ultimately I think it's semantics that relies heavily on context to give a proper meaning.