The motif of victimhood
The motif of victimhood begins with a girl enslaved to her own flesh and blood, her grandmother. This primary victimhood turns into exponentially worse victimhood when her grandmother betrays her. This means that every rape endured by Erendira is compounded with her deeper, more intimate violation, the betrayal of her own family. This means that Erendira is like a Christ-character in a way, because they both represent the same archetype, the suffering servant, but instead of representing the Christ in the typical way of winning by forgiveness and mercy, Erendira represents the apocalyptic Christ, the judge who exacts vengeance.
The symbol of the burned-down house
Erendira lights a candle and burns down her grandmother's home. This is symbolic, surely, and its most fundamental interpretation seems to be that Erendira realized something, like a lightbulb going off, which caused her grandmother to go to great lengths to subjugate Erendira. Maybe it means that Erendira has come to realize that she is the victim of mistreatment, thus destroying the power structure her grandmother had set up, and for this, Erendira suffer's the grandmother's wrath. However, the house falls, regardless, and inevitably, so does the grandmother.
The allegory of romance
When the girl is being turned out to the world, exposed to violation and mistreatment, there is a young boy named Ulises, and whereas the older men can use the girl and throw her away, the young boy is still so vulnerable to love that he can't help but love Erendira. This means he has to come to terms with her reality, and he has to meet her where she's at. If he wants a life with her, it might mean conspiracy to murder her torturous grandmother. In other words, the boy is saving the girl from an evil monster by finding the humility to treat her as a real person. It's an allegory for archetypal romance.
The symbolic murder failures
The meaning of the arsenic attack and the explosion, both of which failed to kill the grandmother, is that Erendira is not committing a crime of passion with her lover, but rather, the two are involved in serious, terroristic level conspiracy against the grandmother. This is not a violent outburst, but rather a cold, calculated decision. This makes the murder a reflection of Erendira's character—good or bad.
The symbol of prostitution
The grandmother submits her daughter to a life of prostitution, so throughout the novel there are accounts of rape, forced by a family member. This is not for nothing. It symbolizes the true betrayal of familial abuse—especially abuse against children. By showing a child that they aren't safe at home, their innocence is violated. Certainly a young, helpless person will become paranoid and traumatized by abuse. It's as if the grandmother turned her out to the world for profit—so the symbol of prostitution makes sense.
