why did minerva slap trujillo at the dance?

Trujillo dances and flirts with Minerva, and she tells him she wants to study in the capital to be a lawyer. But when he implies that he would like to "conquer" her, she says she is "not for conquest." He tells her the university is no place for women, mentioning the "communists and agitators," implying they have been caught. By mistake, Minerva blurts out, "Virgilio Morales?" She must backtrack and pretend she does not know Lio, and Trujillo believes her. When he pulls her inappropriately close, thrusting at her in a vulgar way, she slaps his face.

Source(s): http://www.gradesaver.com/in-the-time-of-the-butterflies/study-guide/section6/