Thanks! Most kind (=
As for the problem, I have tested it and it works. So I assume there's a misunderstanding, what have you tried to do?
To get I'm a sinner, you must level the thought "What have I done" up during the night.
The perk "what have I done" is obtained when you get Sheila to the hj scene and finish.
To get to the hj scene you must unlock the second visit to the priest
That is done by going to the church after you have again bothered Sheila and made her let you continue. As well as get the thought "I must sacrifice myself"
To get those you must engage in the first conversation with the priest.
To do that you must first get Sheila to the thought "Michael is possessed by a demon" and ask the priest to help you with Pranking Sheila.
To get the priest to cooperate you must ask for a favor, to get the favor you must do tasks for the priest.
To get the thought "Michael is possessed by a demon" you must level up the thought "Michael is acting crazy"
To get that thought you must bother Sheila when she is either in the Kitchen at the evening or the Livingroom at noon.
To do that you must get the thought "I must see her naked!"
To get that thought, level up the "Bikini Picture" thought.
To get that thought, search the bedroom cabinet.
Hope it helps.