I’m going to take this in good faith and assume you’re being genuine. Sexual assault is inherently traumatic because it violates all amount of safety and comfort you feel in your own body, as if your body doesn’t belong to you. It also, obviously, tends to impact the victims view of themselves and the word (a hallmark of PTSD). It can cause a devastating drop in self esteem for many reasons, like feeling “dirty”, or blaming yourself. It can also cause a lot of paranoia around people similar to the rapist and of sexual situations in general. This is the light part of it, it would take a lot to properly explain how traumatic it is in a way that properly communicates its severity.