Nor+visited+in+heaven;+Yet+certain+am+I+of+the+spot+As+if+the+chart+were+given.

In this part of the poem the poet is talking about faith. More importantly, her faith, which probably pretty strong since she believes in heaven "as if the @chart were given". This is about faith because unlike the other examples in the poem no one else has seen or has proof that heaven exists. Also even though people have claimed to have spoken with god, no one actually has proof. But the poets piont is that she has faith and thats good enough for her.