About Point of View - avoiding POV Violation
These are words that glue the reader into the particular POV, generally the word knew - Paul knew that Leslie loved apples. However, when overused, filters become the source of loose writing, so authors need vigilance in their use.
These are words and phrases that allow the non-POV character to express their probable point of view, yet maintains the POV established in the section. i.e. She probably knew him. OR Sydney always ate his sandwich with his hand, no doubt (that is when Sydney is not the POV character). These words generally do not cause reader anxiety, or less so than a slip in POV.
Edward C. Patterson