Prettycus oopsus.
The Latin word for mistake is error
Pulcher soror means beautiful sister in latin!
bellam
omnes facit errata
Innocentia pulchra.
Pulcher/pulchra ego.
Pulchra arbor.
Bella Britannia.
To say "beautiful mistake" in Sanskrit, you can use the phrase "सुन्दर भूल" (sundar bhool). The word "सुन्दर" (sundar) means beautiful and "भूल" (bhool) means mistake. Together, they would be written as "सुन्दर भूल" in Sanskrit.
nigrum est pulchra
ille est pulchra
Pulcher/pulchra bos.