It doesn't make sense when you put it into words. The soft-spoken, gentle-hearted nurse, and the loud, easily-irritated engineer. If you wrote down their story, nobody would believe it. It would be a joke, and the punchline would be lurking somewhere, not yet written down.
But when B'Elanna steps into their quarters after a long day, and Kes looks up and their eyes meet and the smile spreads over Kes's lips, an automatic reaction that would be helpless if it wasn't welcomed, somehow, all the tension drains from B'Elanna's shoulders. Their lips meet and any lingering annoyance washes away.
"Hey," B'Elanna always greets her the same way, voice soft in a way nobody but Kes would believe possible.
"Hello," Kes always replies, a warmth in her tone that no one else had heard before.
Because even if they don't make sense when put into words, when they're there, together, it doesn't matter. They fit in a way neither had expected, but both treasure more than anything.