Yes that is part and partial of a plenary indulgence (but not partial…and one may gain many many partial in day…)
Tis I would say a matter of will (and of course of grace) (and remember one may gain one per day…under the usual conditions).
See from the Church:
If one looks at some examples of grants of specific plenary indulgences (Apostolic P.) - it can perhaps be helpful -(remember they are all referring to the same condition).
Current Year of Consecrated Life: “with complete detachment from any sin”
From World Youth day: “in a spirit of total detachment from any sin”
From World Meetings of Families: “in a spirit of total detachment from any sin”
The one from the Birth of St. Paul:
“in a spirit of total detachment from any inclination to sin”
The indulgence on Divine Mercy Sunday:
“in a spirit that is completely detached from the affection for a sin, even a venial sin”
and the same for the one regarding the 40th anno of Vatican II
“in a spirit that is completely detached from affection for any sin”
If one reads thorough those various ways of saying the same condition a few times - that should be helpful.
