"You still don't get it? Minerva, don't you see? Trujillo is having everyone killed!" (1.2.78)
Sinita is the first one to open Minerva's eyes to the violence that pervades the island. She tells it at night, in the dark, as a secret, but it's actually common knowledge to anyone who's got his or her eyes open. This first exposure to violence is secondhand, but influential for Minerva's life trajectory.
There were the Perozos, not a man left in that family. And Martínez Reyna and his wife murdered in their bed, and thousands of Haitians massacred at the border, making the river, they say, still run red—¡Ay, Dios santo! (1.4.73)
The Perozos are Sinita's family, and every man was killed as punishment for her uncles' treason. Virgilio Martínez Reyna was beheaded, he and his wife among Trujillo's earliest victims. The Haitian massacre refers to the "Parsley Massacre" of 1937. All of these examples are just a few of the thousands of atrocities that Trujillo engineered.
A little while ago, I got up and dragged that heavy box out from under. It was nailed shut, but the nails had some give on one side where I could work the lid loose a little. I held the light up close and peered in. I almost dropped that lamp when I realized what I was looking at—enough guns to start a revolution! (2.7.237)
María Teresa is an innocent college girl when she spends a summer with Minerva. But the night that her nosiness gets the best of her and she snoops in the box under her bed, she finds out that the plans her sister and brother-in-law are making involve serious violence. Do you think it's justified?
We piled up the boxes he'd brought in the back room, and then we stood a moment, a strange sadness in our eyes. This work of destruction jarred with what was in our hearts. (2.7.276)
The boxes that Palomino brings to Mate's apartment are full of weapons and explosives. The "work of destruction" refers to the revolutionary plans to invade the island and overthrow Trujillo, and it clashes with the overwhelming feeling of romantic love that is growing between them.
Next thing I knew, His Kingdom was coming down upon the very roof of that retreat house. Explosion after explosion ripped the air. The house shook to its very foundation. Windows shattered, smoke poured in with a horrible smell. (2.8.106)
Patria understands the violence of the invasion in religious terms, calling the shelling "His Kingdom […] coming down." This refers to the end times predicted in the Bible, when Catholics and other Christians believe that God's Kingdom will come to earth and the bad guys will have hell to pay, literally.
I looked in his face. He was a boy no older than Noris. Maybe that's why I cried out, "Get down, son! Get down!" His eyes found mine just as they shot hit him square in the back. I saw the wonder on his young face as the life drained out of him, and I thought, Oh, my God, he's one of mine! (2.8.111)
The vision of the violent death of the young rebel is, for Patria, a turning point in her life. His being shot in the back makes his murder cowardly; he was already on the run, not attacking his killer. Her ability to see him as her child, as equal to all children, inspires her to join the revolution and seek justice for all the innocent children who have been killed by Trujillo's forces.
It was all over the papers the next day. Forty-nine men and boys martyred in those mountains. We had seen the only four saved, and for what? Tortures I didn't want to think of. (2.8.120)
After Patria's retreat that ended in the failed invasion, her revolutionary fire is fueled by the information reported in the paper. It might seem strange that the newspapers include such information rather than censoring it, but perhaps the high numbers of deaths were meant to frighten anyone contemplating an insurrection.
And afterwards we read in the papers how one boat with ninety-three on board had been bombed before it could land; the other with sixty-seven landed, but the army with the help of local campesinos hunted those poor martyrs down. (2.8.121)
The Trujillo regime answers the attacks from Cuba and its own revolutionaries with overwhelming violence, but the real key is that it has the campesinos (peasants) on its side. Patria calls their victims "martyrs" which gives their sacrifice a religious connotation.
It was on that very coffee table on which Noris had once knocked a tooth out tussling with her brother that the plans for the attack were drawn. On January 21st, the day of the Virgin of Highest Grace, the different groups would gather here to arm themselves and receive their last-minute instructions. (2.8.167)
Patria remembers the everyday violence of a brother-sister wrestling match (Noris' lost tooth), and contrasts it with the revolutionary violence she and her group are planning in her living room. Her home is the setting for both kinds of scuffles, but their outcomes are very different.
When he got upset, he would just raise his voice. But that night, he grabbed her by the wrists and shoved her on the bed, only—he said later—to make her come to her senses. "Swear!" (3.9.64)
Jaimito takes a cue from Trujillo and uses violence to keep his family in line. When Dedé wants to help her sisters by burying some arms on their property he reacts with violence. His claim later on, that he wanted to make her come to her senses, attempts to justify his actions, but do you think it's fair to protect someone by using violence?