It's because you're accidentally escaping your text by using the same quotes.
Try:
$videoURL = '.$rowcontentfinal["link"].';
For this reason, I'd recommend sticking to one quote style for strings and one quote style for "code". eg in he above singles for strings and doubles for "code"
Alternately you can try escaping the internal quotes
$videoURL = '.$rowcontentfinal['link'].';
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