Question 1: So lets just say a person does something, but they are not sure if it is mortal or venial…or maybe even a sin at all. Can that count as them still committing a mortal sin, even if they were unsure.
Question 2: Now this question is very much like the last situation but a bit different. Now lets say the person had some sort of slight feeling, or knowledge before hand about how a sin they were about to commit were wrong, but was not sure if it truly was or maybe just did not know the gravity of the sin. Thus they are confused to what sort of sin they committed. In this situation could they be held accountable for mortal sin? (The second question is a little hard for me to explain but I hope you get what I am trying to say

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You can commit a mortal sin an be culpable for it, without even knowing that it is grave. That is because full knowledge does not refer to knowledge of gravity but to the teaching of the Church that it should not be done, and also to your own conscience, and also it is possible to be culpable through neglect to discover what is sinful. Here is something on it in the Catechism of the Catholic Church, and from
CAF.
“The kind of consent needed, more technically, is the degree of consent needed to make a fully human act. This does not mean saying, “Yes! I want to do something
really evil!” and having no reticence about it. One
can have misgivings, regrets, mixed feelings, et cetera and still give deliberate consent to an action. Similarly, one does not have to know with metaphysical certitude that a given act is gravely sinful. Lesser degrees of knowledge will also count—again, the degree of knowledge needed for an authentically human act is the key.”
catholic.com/quickquestions/if-someone-is-unsure-about-whether-a-sin-is-mortal-or-not-doesnt-that-mean-it-isnt-mo1790 A human being must always obey the certain judgment of his conscience. If he were deliberately to act against it, he would condemn himself. Yet it can happen that moral conscience remains in ignorance and makes erroneous judgments about acts to be performed or already committed. **
1791** This ignorance can often be imputed to personal responsibility. This is the case when a man “takes little trouble to find out what is true and good, or when conscience is by degrees almost blinded through the habit of committing sin.” 59 In such cases, the person is culpable for the evil he commits.
1859 Mortal sin requires
full knowledge and
complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart133 do not diminish, but rather increase, the voluntary character of a sin.