What virtue listed means responsibility, seriousness and commitment in Ancient Rome?

The Roman virtues are a series of values esteemed in Ancient Rome as fundamental for all Roman citizens. They are qualities of life to which all Roman citizens (and, ideally, all others as well) should aspire.

They are the heart of the Via Romana and for many historians it was these qualities that gave the Roman Republic the necessary moral strength to conquer and civilize the world. They were divided into personal and public.

There were 15 personal virtues, among them was the gravitas, one of the most appreciated together with the pietas, the dignitas and the virtus.

Gravitas that denoted "seriousness", it's also translated variously as weight, dignity, and importance and connotes restraint and moral rigor. It also conveys a sense of responsibility and commitment to the task.

For the ancient Romans gravitas was the highest of the fourteen virtues. A man who possessed gravitas recognized the importance of the matter at hand. He had a strong sense of responsibility and was not given to frivolous behavior or excessive levity.

Many Roman philosophers praised constantia (perseverance, endurance, and courage), dignitas and gravitas as the most important virtues; this is because it made dignified men capable. These are additional concepts that accompany Roman actions. The men of the ruling upper and upper-middle classes were educated in a public school system where Classical language and literature formed basic elements of the curriculum.