The Vixen War Bride by Thomas Doscher
Book 1 of the series. I don't think the title very good, actually. . . .
Captain Ben Gibson, and a fair number of his soldiers, are from a planet that had its entire population obliterated in a war with aliens that have fox tails and ears. Which war is now over, and he's part of the occupying forces. (There's a brief discussion of whether it's longer odds that they visited Earth, or we just happened to imagine creatures like them.)
The village near their base is inhabited only by the elderly. There are many reports, about the planet, of insurgent attacks. Electronics, in particular radios, do not function reliably. And then, out of the blue, a younger fox woman appears, confessing to atrocities.
The plot goes on, including a cave entrance that is all but blocked, more confessions, winning trust with a knife, the reaction of females of both races to something the males do, learning the language (which is barely known to anyone human at the start), fighting a local creature, persuading the aliens to leave a cave, much culture clash and issues caused by ignorance, and more.