No current sovereign country uses a national flag that is only pink and white.
Pink is rare in national flags. Ask why and the answer is practical. Historically, durable pink dyes were hard to make. Flags need strong, bright colors that last in sun and salt air. Nations choose bold colors that show well at a distance and in bad weather. Pink often fades or looks weak on the battlefield or at sea.
Also, heraldry and vexillology favor a small palette. Red, blue, green, black, white, and yellow are common. Pink sits between white and red and is not a standard heraldic tincture. Many countries use red and white instead. For example, Japan, Indonesia/Monaco, and Austria use red and white and can look pinkish if the fabric fades or a photo washes out. Consider these red-and-white flags as the closest national matches.
Consider related categories instead. Some municipal and regional flags use rose or pale red tones. Pride flags include pink and white (for example, the transgender pride flag uses pink, white, and blue). Historical banners and special ceremonial flags sometimes show pale reds. Check flag databases such as FOTW, Wikimedia Commons, and official government pages for images and blazons if you want examples and pictures.
