Given two pairs of quantum states, we want to decide if there exists a quantum channel that transforms one pair into the other. The theory of quantum statistical comparison and quantum relative majorization provides necessary and sufficient conditions for such a transformation to exist, but such conditions are typically difficult to check in practice. Here, by building upon work by Matsumoto, we relax the problem by allowing for small errors in one of the transformations. In this way, a simple sufficient condition can be formulated in terms of one-shot relative entropies of the two pairs. In the asymptotic setting where we consider sequences of state pairs, under some mild convergence conditions, this implies that the quantum relative entropy is the only relevant quantity deciding when a pairwise state transformation is possible. More precisely, if the relative entropy of the initial state pair is strictly larger compared to the relative entropy of the target state pair, then a transformation with exponentially vanishing error is possible. On the other hand, if the relative entropy of the target state is strictly larger, then any such transformation will have an error converging exponentially to one. As an immediate consequence, we show that the rate at which pairs of states can be transformed into each other is given by the ratio of their relative entropies. We discuss applications to the resource theories of athermality and coherence. * marco.tomamichel@uts.edu.au 1 A transformation is said to be bistochastic if it transforms probability distributions to probability distributions, while keeping the uniform distribution fixed.The majorization preorder is particularly relevant and useful because of a famous result by Hardy, Littlewood, and Polya, according to which the relation p 1 p 2 can be expressed in terms of a finite set of inequalities [22] of the form f i ( p 1 ) ≥ f i ( p 2 ), intuitively capturing the idea that p 1 is "less uniform" than p 2 . Such inequalities can be conveniently visualized by plotting the Lorenz curve of p 1 versus that of p 2 [32].As it involves the comparison of two probability distributions relative to a third one (i.e., the uniform distribution), the majorization preorder is naturally generalized by considering two pairs of probability distributions, that is, two dichotomies ( p 1 , q 1 ) and ( p 2 , q 2 ), where now q 1 and q 2 are arbitrary distributions. One then writes ( p 1 , q 1 ) ( p 2 , q 2 ) whenever there exists a stochastic transformation simultaneously mapping p 1 to p 2 and q 1 to q 2 . As a consequence of Blackwell's equivalence theorem [5], also the more general case of dichotomies is completely characterized by a finite set of simple inequalities, which directly reduce to those of Hardy, Littlewood and Polya if q 1 and q 2 are both taken to be uniform. Also in this more general scenario, a relative Lorenz curve can be associated to each dichotomy, and the preorder visualized accordingly [45].In relation to quantum information sciences, while the preorder of majoriz...