Comely: having a pleasing appearance.
"Beautiful" is commonly used when writing and more often than not, it is overused. Though in the past, the word comely was used to describe a scene or an inanimate thing, it's now also used to describe a person.
Example: The girl looked incredibly comely in the ball gown.
It's not a difficult word to use, and it could be just the synonym you've been looking for.
Until next time...
Stay Curious ;)