While a Personaggio is joined to a unit containing Guardia del Corpo and the Personaggio fulfills at least one of the requirements defined by X that, Personaggio then benefits from [stubborn]Determinato.
In addition, if the unit it is joined to has at least one Proper Rank, the unit is considered to be Steadfast for the purposes of Break Tests.
Note: units entirely with Instabile do not take Break Tests.