How do you know if something traumatic really happened or not?

I feel like our father knows what he did to me in the past but I never knew the truth. I have fragmented memories from a long time ago where I was r+ped twice by him and I don't know if they're fake memories or if it happened for real. Later on I noticed some red flags about him which could confirm what he did, but I'm still not sure. I haven't found a good therapist to discuss it yet, but in the meantime I wanted to ask if you guys had some advices or similar experiences about this. The doubt is driving me crazy, but I can't ask him directly because I cut off contacts and I'm terrified of him. Also, about the therapist, what kind of training should they have? Because every time I see one they say "sorry, I'm not trained for this"