The claim
Title tags and meta descriptions are strong inputs but not guaranteed outputs; Google can rewrite them, so clarity and query-alignment matter more than exact wording control.
What the evidence shows
Google's documentation on title links and snippets explains that it uses the page's title element and on-page content but may substitute more relevant text when the original is poor, truncated or query-mismatched. Well-written, descriptive, unique titles and content are the most reliable way to influence - though not dictate - what appears.