。
She knows me.
Literal
She [topic-は] me [object-を] knows.
知っている is the standard way to say 'know' as a state — the bare 知る ('come to know') is almost always used in this resultative ~ている form when it means 'know X.' This makes the verb behave very differently from English: 知る on its own would suggest the moment of learning, not the state of knowing. The negative form 知らない ('don't know'), oddly enough, drops the ~ている, giving an asymmetry beginners often trip on.