Meaning: Mountain Princess / Princess of the Mountains
If the context is a name or title, it is often written as one word in English transliteration: yama no hime
The most accurate and natural rendering of in solid text (without spaces or capitalization changes) is: Meaning: Mountain Princess / Princess of the Mountains
However, if you need to preserve the original romanized Japanese word boundaries while using solid text (i.e., no spaces but clear reading), the standard way is: no spaces but clear reading)