hook line and sinker

The phrase "hook, line, and sinker" is an idiom that means to completely and unquestionably believe something or be completely fooled by it. It is often used when someone is easily deceived or falls for a trick or deception without any skepticism or doubt. The term comes from fishing, where the hook, line, and sinker are the three components used to catch fish. In the context of the idiom, it implies being caught or fooled completely, just like a fish that swallows the bait along with the hook, line, and sinker.