Your hero needs a way to get to the king. His noble cousin could introduce him -- but when he first appears, he is hell-bent on persuading your hero to give it up.
The magical sword that will, in the end, be needed to kill something -- wielding it is so much more difficult than his old sword that your hero is just about useless in a fight. (And his old sword broke so he really is stuck using the magical sword.)
The love-interest as an endless fight is so familiar as to be cliche -- but respect your cliches. A cliche is something that gets used lots and lots and lots. Nothing gets used lots and lots and lots without having something going for it.
You can do it the other way around, of course, with bad stuff disguised as good stuff. Introduce the villain of the piece as a friendly rival, even willing to be an ally until he realizes that the hero seriously could triumph. Etc. It introduces the same element of irony when the truth comes out.
But it's much more useful for the good stuff because you want to disguise it. Hosing down your hero is not something you have to justify, and it increases tension. Ladling on the good stuff is dangerous because it makes the tension slacken. (And arouses charges of Mary-Sue-dom. Hosing down your character the wrong way will do that too, but good stuff is particularly dangerous.)