The unsettling realization about Virgilio, nicknamed Lio, that Dede comes to is that he is really a Communist.
Lio is "a radical young man" who, for a period of time, was a close friend of the Mirabals. Dede had had an infatuation for him at first, but it turned out to be Minerva who had developed a really close relationship with him, which she claimed was strictly political. Lio had had a great influence on the Mirabal sisters in that he was the first acquaintance they had made who "presented a very real opportunity to fight against the regime".
One Sunday afternoon, after the family had not seen Lio for a long period of time, Mate reads a newspaper article about a "demonstration at the university, led by a bunch of young professors, all members of the Communist party. Among the names listed (is) that of Virgilio Morales". Although this information comes as no surprise to Minerva and Dede's beau Jaimito, Dede herself is aghast. She
"had never known an enemy of state before. She had assumed such people would be self-serving and wicked, low-class criminals. But Lio (is) a fine young man with lofty ideals and a compassionate heart".
The revelation that Lio is a Communist brings Dede to the realization that they are - "as Minerva like(s) to say - (living) in a police state", and as a result of this new understanding, Dede's sense of political awareness is awakened. She begins "to read the paper with pointed interest...evaluat(ing) and reflect(ing) over what she read(s)". Her newfound knowledge is confusing to her, and she is not at all sure "what (she is) going to do about it now that she (does) know" (Chapter 5).