I think "She knows him" should also be acceptable, if "She knows it" is accepted. "Lo" is the indirect object pronoun for it/him, unless I am mistaken?
When you're talking about knowing a person, you have to use "conoscere" instead of "sapere".
But the feminine accusative is "la", like "darla le mele"(give her the apples). How can "Lo sa" refer to "SHE knows"?
Wait, you're a little confused :P
It's true that "la" is the feminine accusative, but the sentence would be "darle le mele" because her would be dative, and the apples would be accusative if that form still existed.
In "she knows it", "she" is nominative and "it"/"lo" is accusative: it can refer to any masculine noun, and even to an unspecified object, as masculine tends to be the default gender.
OK, that's fine. I really got confused because I have a clitics table helping me. You might take a look into it. "A lexical analysis of Italian Clitics", by Paola Monachesi. That's why I couldn't find the respective use for "te" and "me", but I will get it soon.
What it's referring to is "She knows [it]", so the "lo" refers not to "she," but to whatever the thing is that she knows. For example, you could ask if she knows that the party is on Friday, and you could respond "Lo sa." The "lo" refers to that fact.
She knows, which is the translation given by DL = Lei sa. I don't get this whole discussion, or the presence of "lo'. To me "lo sa" says "He/She knows it".
Hmmm, - I am confused. Lo = it and sa = he/she/it/You knows . . so could it also mean he/it/You knows ?
So let me get this straight, "lo sa" means "she knows it", so technically the full sentence would be "lei lo sa" but we don't need to put "lei" since "sa" is the conjugated form that already implies who is being discussed?
"Lo" means "it" and "sa" means "he/she/it knows", (the conjugation in third person for sapere, - to know). "Lo sa" literally means "It he/she/it knows", - but to turn that into proper English you have to change the word order.