plagriarism

Could it be a possibility that plagiarism checker tools may be stealing your work (content) ? No matter even if they claim "We do not store your shit, your shit gets deleted instantly bla bla bla". It could be possible that they sell the content of people who use their plagiarism checker tools...

Hi I tried a French article on both sites, but the results were different, 1text : Check for plagiarism Unique: 41.72% smallseotools: Check for plagiarism Unique: 90.00% what do you think? What result will I rely on?