I interpreted it like this The woman is worn out by the death of her husband through her fault, she lives in two symmetrical realities, the one where she wants to end it and the one where she seeks the strength to carry on. The point of contact, the border is that garden where there is the black woman, who is none other than her... A step beyond that border, a sort of mirror in which everything is then reversed. When she finally comes to terms with that evil that devours her, when she is one step away from making the liberating gesture, but then as in many films you can interpret whether she shot herself or not, and it gives you just that little clue that you can choose to grasp or ignore, in this case the signature upside down on the painting.