Yes, I agree with Ruskie, you need to check for yourself, looking at original records wherever possible.
Being on an Ancestry tree doesn't make it true, although lots of people will assume it is, and copy it, making it look more credible than it is.
Ancestry does have access to many documents, but there are lots more that aren't on Ancestry.
Also, while Amphillis is an unusual name, it's not uncommon for unusual names to be repeated within families, so it's possible that she had a cousin of similar age with the same name.
Good luck!