It's understandable that you're feeling conflicted and suspicious about the situation with the girl you're seeing. Here are some insights and suggestions on how to navigate this complex scenario:

1. Open Communication

It's crucial to establish open and honest communication with her. Share your feelings and concerns without accusing her. You might say something like:

"I really like you and I want to trust you, but I can't help feeling uneasy about your living situation and your past with the roommates. Can we talk about it?"

This encourages her to share her perspective and can help reassure you about her intentions.

2. Set Boundaries

If you're both serious about your relationship, you may want to discuss boundaries regarding her interactions with her roommates. For example:

"I think it would be best for our relationship if you set some boundaries with your roommates, especially since there’s a complicated history. How do you feel about that?"

This shows that you care about her well-being and your relationship while also addressing your concerns.

3. Trust Your Instincts

While it's important to give her the benefit of the doubt, it's equally essential to trust your instincts. If something feels off, don’t ignore it. You could consider:

"I want to believe you, but I need to feel secure in our relationship. What can we do to build that trust?"

This statement expresses your need for reassurance and encourages her to engage in building trust together.

4. Assess Your Comfort Level

Reflect on whether you're comfortable with her living situation. If her past with the roommates continues to bother you, it might be worth discussing alternative living arrangements. You can ask:

"How do you feel about finding a new place to live? I think it might help both of us feel more secure."

5. Observe Behavior Changes

Pay attention to any changes in her behavior or your relationship dynamics. If she becomes distant or secretive, it might be a sign to address your concerns again. You could communicate this by saying:

"I've noticed some changes lately, and I'm feeling a bit insecure. Can we talk about what's going on?"

6. Seek Support

Consider discussing your feelings with friends or a therapist who can provide an outside perspective. Sometimes, talking it out can clarify your thoughts and feelings.

7. Be Prepared for Outcomes

Ultimately, be prepared for any outcome. If she is genuinely committed to you and your relationship, she will understand your concerns and work with you to address them. However, if she dismisses your feelings or continues to engage with her roommates in a way that makes you uncomfortable, it may be time to reevaluate the relationship.

In conclusion, relationships can be complex, especially when past entanglements are involved. Engaging in open communication, setting boundaries, and trusting your instincts will be vital as you navigate this situation. Remember, your feelings are valid, and it's essential to prioritize your emotional health as well.