There are a number of strong reasons for believing Ellen White was not an ordinary woman.
First, hundreds of people witnessed her in vision. It is reported that physicians would examine her while she was in a trance like state and observed that she stopped breathing for hours while maintaining a healthy skin tone and normal blood flow. Others would poke her to get a reaction but she was completely oblivious to her surroundings while her mind was in heaven.
Second, there are eyewitness accounts of people who saw her speaking to angelic beings while at her writing desk in the dark hours of the night.
Third, she describes the nature and character of God as being eternal, all powerful, all knowing, everpresent, and full of self-sacrificing love for His creation. She speaks of the full deity of Christ and the Holy Spirit. She acknowledged the Bible as the inerrant word of God that points people to Jesus and his death on the cross for the sins of lost humanity.
Stephen Beagles (2024)