Please post a picture of the bedroom, bedding, and everything that will be in that bedroom.

how much natural light? what direction? agree with @lisedv photos of all the colors .

Photos don't render colors accurately, but it couldn't hurt to see the entire room.

You could try some of the Ben Moore Historical Colors in tans/beiges. Not sure how light or dark you want to go, but lots of them can work with green. I'd suggest Manchester Tan, Lenox Tan, Huntington Beige, Bleeker Beige, Wheeling Neutral, Crown Point Sand, for a start.

And then get large samples and view them in the room, during the day and evening, in natural and artificial light. Colors will appear differently depending on the light. Only you with your own eyes in the room can determine the best color.

You didn't say how light/dark you want the color to be. Diana Bier made some good suggestions, but I will say I have Crown Point Sand in a room and it doesn't go with sage green. Do you want something lighter? SW Alabaster, BM White Dove? Or look for a lighter version of the sage green you have on the bedding. My bedroom in my previous house was done that way.

Are there other colors in the bedding or room accessories?

Alabaster and White Dove are essentially white. And it’s possible that Crown Point Sand doesn’t work with sage green in your room, kAndrews but it could elsewhere.

Pick up a fan deck from your favorite paint company. They run under $40. It will save you many trips to the store to get paint chips that turn out to be all wrong. Once you have picked out a few good colors, buy sample quarts and try them out.

BTW, it's probably the beige carpet whose color tones you will want to work with in choosing a tan, beige or off white. The sage green bedding will go with far more colors than the beige carpet.

Nothing like a white color wash for walls, trim and ceiling to open up a room.

Ben Moore Swiss Coffee is a nice warm white. They pair it with Lush sage so it will work with your colors.

It's much more economical to purchase samples of the colors than to buy a few sample quarts, which run about $23 each. Buying 5 of them and not liking any is a sure way to throw away over $100.

A color consultant could get you the samples for free. But many non-pros here recommend Samplize, and they cost about $6 each.

@Diana Bier, yes, the quarts do add up. Samplize is a good option. When you are paying pro painters $1000 to paint a room, it's good to be sure of the color before they start.

Just to give you an idea, I probably consider LOTS more than 5 or 10 colors for a room. When you think a color might work, and then see it in the room, it could look very wrong. It's easier to tack up more samples than to start painting them on the wall.

Here are a few sage green colour scheme ideas. See how not seeing your room nor what your actually plan on using can affect the colour suggestions.