What is Trujillo's motivation in In the Time of the Butterflies?
Trujillo, as befits his role of dictator of this novel, has but one motivation: to do everything he can to sustain and continue his autocratic regime that allows him to do anything he wants and to maintain an iron fist of control over the population of the Dominican Republic. Throughout the novel, Trujillo is presented as a figure who knows what he wants and whose will is only matched by that of the will of Minerva, as she imagines after she gambles for her future:
I look down at the lopsided scales as he puts his dice back. For a moment, I imagine them evenly balanced, his will on one side, mine on the other.
However, it is clear that Trujillo is not used to meeting people who stand up to him, as he has his pick of women and expects even the wives of his officials to sleep with him, as Minerva realises when she goes to the banquet at el Jefe's residence:
Under the tablecloth, a hand is exploring the inner folds of a woman's thigh. I work it out and realise it is Trujillo's hand fondling the senator's wife.
The motivation of Trujillo is therefore to do whatever he needs to do in order to sustain his power and continue in the kind of unchallenged position he occupies where he can do anything he wants without consequences. It is of course this motivation that the Mirabel sisters are willing to die to oppose.