Your room is already divided in two horizontally by the chair rail or the wainscoting.
Paint one room two colors.
An accent wall is the perfect frame for a wall hung art collection or a single important piece.
It also depends on your bedding though.
If you choose to contrast the ceiling making it darker than the walls may create a dramatic effect.
How to paint a room with two different colors accent walls.
Complementary and split complentary colors.
If it is mainly the orange then you might want the pink on 3 and the orange as the accent.
Chair rails and wainscoting.
Colorists often utilize a color wheel before selecting a multicolor design scheme and some paint.
When selecting two colors for one room it is important to choose one that is a white or more neutral in color as not to compete or fight with the accent color.
Both of these colors can make your room look more coordinated.
Looking for more balance purple and white is good option.
Rules of painting a room with two colors color science 101.
Complementary colors provide strong contrasts that are visually striking.
You can try these complementary colors for your bedroom or living room.
In this case the darker pink as otherwise the room might be too dark if 3 walls are the dark pink.
The triad color.
Purple and white are a good complement.