“You’ll like the way you look, I guarantee it,” said the guy who used to run Men’s Wearhouse.

It’s hard to guarantee something as subjective as that, isn’t it? You’ll love this, really. But no matter how certain you are that Sam will like green eggs and ham, you wouldn’t want to guarantee it.

Same way you’re guaranteed internet speed, server uptimes, pizza delivery windows, and so on. This is because the very term ‘guarantee’, in this age of winning us with half-truths, has been reappropriated to suit the vast majority of situations in which it’s now used — situations in which a guarantee is in fact impossible.

‘Guarantee’ originally meant something like a pledge of truth, that someone would absolutely confirm something, or assure you of some future event. This would have to be verifiable by both parties, of course. So I could guarantee that this dog is purebred, and DNA testing could confirm it if necessary. I guarantee this chicken is roasted to an internal  temperature of at least 165 degrees. I guarantee this Barry Manilow ticket is genuine.

But clearly I can’t guarantee you will like your suit. What ‘guarantee’ means there is that I feel I have it in my power to provide you with a suit you’ll like, and I’ll do my very best to make you happy up to and including not charging you anything if I’m unsuccessful.

‘Guarantee’ is further bastardized by internet providers who use it to mean they will at most discount your bill, perhaps, if you notice that they failed to provide the service that they guaranteed.

Then there’s maybe the most extreme example, which manages to drag ‘guarantee’ all the way down to the level of ‘attempt’. We will attempt, they mean, when they say we will guarantee returns of x% on your investment. They can do this with the assistance of an asterisk ‘*’, which itself has become a little grammatical flag indicating that the preceding assertion is not, in fact, true.

“We guarantee a return on your initial investment of at least 10%*”

*Our liability limited to the return of part or all of your initial investment, at our sole discretion.

So a word that used to mean you could be certain that whatever was asserted would in fact turn out to be true one way or another has become almost entirely its opposite. When you see the word ‘guarantee’, you know that whatever it means may well require several pages of legalese that you could never fully understand, but which you may be required to sign.

Exclusions may apply. Limitations will be placed. Requirements must be met. Some of the interpretive smallprint place more of an onus on the guaranteed than on the guarantor.

So ‘guarantee’ in practice means something more like: we admit you will expect something here to be guaranteed, and the fact that we claim to guarantee it means that we’d like you to think it is, but it probably isn’t.

The guarantee’s job is to convince you you’ve been promised the world, while limiting actual liability to — oh, I don’t know — a packet of chips and a pickled egg*.

*Subject to seasonal availability.