im gonna try to keep this as brief as possible

Im a senior in HS with LTR of 5 months (we’ll call her A) , everything going relatively smoothly. yesterday heard from a friend that there was a rumor that she cheated on me and found out who had the info and talked to him. he told me that A’s best friend friend (who has since had a huge falling out with A) had told him that A hooked up with a guy at a party a couple months ago. When i was talking with him he asked A’s friend about it again to get more info but she just denied she ever said that. She said she was talking about a different time where they were with a few guys and A was acting sus but doesn’t think she did anything. So now I have 2 potential situations that I have no other info on and don’t even know if the party thing even happened. I already knew about the time she and her friend were with guys and I was confident she didn’t do anything. but since she and her friend have had a huge fallout and have been shit talking each other for a while, I have no idea why A’s friend would cover for her and lie.

Of course if I knew she was cheating I would hard next but there isn’t enough info for me to know who is telling the truth. Any thoughts on how I should handle this?