I currently live with 2 roommates. When moving in together, the established “rules” for the apartment were that to move in, you needed to be shomer shabbos and shomer kashrus. Since this time, I have started to distrust one of my roommates on this. She commented to me on Shabbos that she wanted to go to her room to make a phone call (I did not see or hear the phone call). She also has stated that she does not care to open the fridge on shabbos if we have forgotten to turn the light off, and she has does this many times. Additionally, this roommate brought home not kosher cheese and showed it to me. I have not seen her eat it; however, she has commented on being excited to eat the cheese and I have seen the cheese diminish in the fridge. I do not know what the halachos are. Do I continue to act as if she keeps all halachos? Can I assume the pots/pans are kosher? Do I have to assume that they are not? Are there any specific ramifications for this— ie only mivushal wine? Thank you!
From what you are describing it sounds like her being religious is very questionable, however I wouldn’t jump to conclusions yet, as it is still possible that she doesn’t know certain things and that there were certain mistakes that she made. Therefore, before we establish that she is indeed not religious, I would suggest that you first talk to her about it. You can do it during a conversation with her, and steer the conversation to this topic, and see what she says, and how she reacts. After talking with her, let me know what she says. I would rather take this approach before making a decision based solely on the examples that you gave.
I hope it goes well