Bible Dictionary
TROW
“Trow” is an obsolete English verb meaning “to believe.” In the King James Version it appears in Luke 17:9 in the phrase “I trow not,” though the words are omitted in later translations because they are considered a textual gloss.
Biblical Usage
The King James Version uses “I trow not” in Luke 17:9 as an answer to a question about whether a servant would be thanked. Later versions omit the expression because the underlying words are regarded as a later gloss.