POLONIUS For Lord Hamlet,
Believe so much in him that he is young
And with a larger tether may he walk
Than may be given you. In few, Ophelia,
Do not believe his vows, for they are brokers
Not of that dye which their investments show
But mere implorators of unholy suits
Breathing like sanctified and pious bonds
The better to beguile. (1.3.122-130)
For Lord Hamlet—and there can be emphasis on Lord, remember that he’s the PRINCE, he’s out of your league, at least in terms of rank—believe so much in him that he is young—immature, we might say, he’s still got some growing up to do, he’s rash, impetuous—and, more importantly, with a larger tether may he walk than may be given you. He’s the PRINCE, and he’s a BOY: he can do stuff that you can’t; he can get away with more; he’s not got as much to lose. He’s got more agency, is less likely to be judged, as Polonius doesn’t say. (Although the image of Hamlet as tethered, like an animal on a rope—a long rope, but still a rope—is an interesting one.) In few, Ophelia, to summarise and cut to the chase: do not believe his vows. Not a word of it. All of those oaths, all of those fancy words: he’s just dressing up his base lusts in poetry and protestation; he only wants One Thing. He’s soliciting you for immoral purposes, and his vows are his go-betweens, they are not of that dye which their investments show, nowhere near as good as they’re painted, but mere implorators of unholy suits breathing like sanctified and pious bonds the better to beguile. It’s all an act! It’s fraudulent, hypocritical; he’s trying to entrap and enchant you. He’s trying to SEDUCE you with WORDS.
You what? Ophelia might be justified in saying. Although Polonius is being stern in some ways he’s also being so delicate, so circumlocutory that she could well not have a clue—this of course depends on how worldly Ophelia is (pretty worldly, in many recent productions, in which she might as well say, dad, I know what you’re on about, I can look after myself and that ship has, as they say, sailed).