It should not show up after sealing. However, sealing is not immediate and can take a year depending on what the sentence was.
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I have never heard of an employer paying to have something sealed for a potential employee, but I could imagine circumstances where it would make sense.
This answer does not constitute legal advice and you should contact an attorney to confirm or research further any statements made in this answer. Any statements of fact or law I have made in this answer pertain solely to New York State and should not be relied upon in any way in any other jurisdiction.