I think it would look nice, especially if your dark wall is on the end of a longer shaped room. If you paint the longest wall in your room the dark color, it will make your room seem narrower; unless you put your sage sofa on one of the white walls for contrast. But color wise, it's a good choice. Also...If you use some brown curtains, roll ups, or roman shades on your windows,(if they're on your white walls), I think it will pull your colors together better. Or try finding a print or multi-toned fabric with all 3 colors in them. That would look awesome !! Have fun decorating !!
P.s.) If your windows are all on your dark wall, then go with using a sage or multi-toned curtain as above.
P.s.) If your windows are all on your dark wall, then go with using a sage or multi-toned curtain as above.