Luann believes that people should tell it like it is when communicating with others because being up-front saves time and energy in the long run. luann's guiding principle in verbal communication is

Luann's guiding principle in verbal communication is directness.

Direct communication is a communication style that is direct, to the point and "does not beat around the bush". There is no pretense or hidden/ implied messages. 

An advantage of direct communication is that it is clear and does not lead to misunderstandings. 

A disadvantage of direct communication is that it can be blunt and harsh, leading to hurting others' feelings. 

The answer for this question would be the directness principle in communication. In terms of speech, directness could be understood as matching the act with the grammatical structure it most usually takes. It can be a question, a command, or even a statement.