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Let's see if you can get an idea of what "dispositive" means.
From the LawNerds.com, Inc. website.
"Often the courts will say 'no single factor is dispositive,'
meaning that one fact or set of facts won't decide the case."
From the Google cached (Florida) Monroe County Sheriff's
Office web page.
"... but the Supreme Court found a single one dispositive
(meaning that it 'disposed of' the matter - that single
issue by itself required a new trial, so the court did not
need to deal with the other issues.)"
So, dispositive comes from dispose. Let's define dispose; from
the Lexico Publishing Group, LLC. website, Dictionary.com.
To settle or decide a matter.
To attend to; settle: disposed of the problem quickly.
To get rid of; throw out.
So, to rephrase your example using other terms:
"I'm not sure that [something] is enough to settle,
dispose, dismiss or throw out your case."
If you need any clarification, feel free to ask.
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