... is a short novel by Kingsley Amis. Its main protagonist may not be the cleverest person in the world but below is some sensible-albeit-dispassionate advice from him;
People get themselves all steamed up about whether they're in love or not, and can't work it out, and their decisions go all to pot. It's happening every day. They ought to realise that the love part's perfectly easy; the hard part is the working out, not about love, but about what they're going to do. The difference is that they can get their brains going on that, instead of taking the sound of the word "love" as a signal for switching them off. They can get somewhere, instead of indulging in a sort of orgy of emotional self-catechising about how you know you're in love, and what love is anyway, and all the rest of it. You don't ask yourself what greengages are, or how you know whether you like them or not, do you? Right?