The speaker admits to being fooled completely. "Hook, line and sinker" is a fishing phrase, and it fits: they took the bait and swallowed it whole. But the poem doesn't stop at embarrassment. The last two lines turn into a kind of defense. A lie that tells you exactly what you needed to hear is hard to resist, because it feels like relief.
The tone is quiet and a little rueful. There's no anger here, and no dramatic scene. The speaker sounds like someone looking back, half-shrugging, half-wincing at their own gullibility. The final question is the heart of it. It isn't really asking for an answer. It's an excuse, and maybe also a confession that wanting something badly makes us easy to trick.
The title and subtitle, "With A Grain Of Salt," add a wry note. That phrase means to doubt something, which is exactly what the speaker failed to do. The lowercase "i" and short lines make the voice feel plain and unguarded, like a private admission.