Her daughters would seek her out at night when she seemed to have a moment to talk to them: they were having trouble at school or they wanted her to persuade their father to give them permission to go into the city or to a shopping mall or a movie – in broad daylight, Mami! Laura would wave them out of her room. "The problem with you girls . . ." The problem boiled down to the fact that they wanted to become Americans and their father – and their mother, too, at first – would have none of it.

–“Daughter of Invention,"
Julia Alvarez

What is the meaning of the idiom underlined in the passage?

The meaning of the idiom "boiled down to" in the passage is that the problem was simplified or reduced to a specific issue.

The idiom underlined in the passage is "to have none of it."

The meaning of the idiom "to have none of it" is to refuse to accept or tolerate something, to reject or be opposed to an idea or proposal. In this context, it means that the father and initially the mother are strongly opposed to the idea of their daughters wanting to become Americans. They do not support or agree with their daughters' desire to assimilate into American culture.

The idiom "to have none of it" means to strongly refuse or reject something. In the context of the passage, it suggests that the narrator's father (and initially her mother) strongly refused or rejected the idea of their daughters wanting to become Americans.