When Aravis first meets Queen Lucy, the two strike up an instant friendship, despite Aravis being a Calormene and a complete stranger. This is not merely due to Aravis' ordeals and Lucy being an All-Loving Hero, but because they feel a natural kinship. Lucy, as the youngest of four siblings, has always felt somewhat marginalized and neglected, and Aravis of course, being promised to a much older man she doesn't even know, definitely knows what oppression is like. They are also much alike, both being tomboys in largely male-dominated societies (though Narnia is vastly more egalitarian than Calormen). But the reason Aravis latches on to Lucy so swiftly and strongly is because Lucy shows that a woman can be a stalwart fighter on par with men, (and be highly admired and respected for doing so), yet still maintain her femininity and love for fancy dresses and such. And one can't help but imagine that Queen Susan and Lasaraleen would also get along famously, though for diametrically opposed reasons.