If I want Leonard to eat a banana, is this a desire that Leonard eat a banana or a desire that Leonard eats a banana? How about a desire that my best friend like me / my best friend likes me? Would using the subjunctive in the second case suggest that this is a counterfactual desire?
The subjunctive in English is optional. Hence
I desire that he eat a banana
I desire that he eats a banana
are both correct. And both are non-idiomatic.
It is much more idiomatic to say "I want my friend to eat a banana" or "I want my friend to like me."
You might use the subjunctive in highly formal situations. These are exceptionally rare and most learners will never be in a situation in which the subjunctive is the best choice.
His Majesty the King desires that he be taken from this place.