A possible synonym for “born witness” could be “bear testimony”.
When we say “born witness”, we mean to see and attest to something. Similarly, “bear testimony” implies giving evidence or proof of something. For example, “He born witness to the event.” could be rephrased as “He bore testimony to the event.” In both cases, the person is providing an account or verification of what occurred.
Another synonym could be “give witness”. This also conveys the idea of providing evidence or being a witness to something. For instance, “She gave witness to the crime.” It shows that the person is offering their account of what they saw.
“testify to” is also a good alternative. It means to provide evidence or affirm something. For example, “The documents testify to his innocence.” This indicates that the documents serve as proof of his innocence, similar to the idea of “born witness”.