Related tones, different texture.
A natural curtain beside a warm neutral wall can feel coherent without an exact match. White fabric may look cooler than expected. Hold the fabric sample directly beside the paint sample.
Do not guess measurements from a picture.
Measure the existing rail and the drop from the hanging point. Check whether the listing is one panel or a pair. Fullness, hemming, shrinkage and radiators affect the choice. An illustration does not replace these measurements.
Screen colors are a guide. Test physical samples in your home.
Keep exploring
What paint colors work with a gray couch?
What paint colors work with a beige couch?
Warm paint colors for your living room
Paint colors for a low-light living room
How to match rugs and wall colors