According you, what is the most difficult thing to drive: project management or project development?

i believe that hard or easy is relate to your mindset and trust in your self , but you can say project development need more effort in mart ways as you need to repair previous faults and also you need to do something tangiable to have the suitable criedt ,the diference between them as you have students first (managment) was fail all time and if you help him to have50% so you have made achieved to make him pass and may that not cost you great effort , the other student (development) is student used to succeed with95% and you help him to have98% the change not seen for alot of people but that cost you harder effort 

it depends on ones expertise of course, while project development focuses on the business side of the project, from feasibility studies, execution and closing etc. Basically, it is business oriented. I'll choose, project management to be my forte at this point in time.

I see hat project development is the hardest of the two.

I believe that every thing is created twice. The first creation is the conceptual (mental) creation. The second creation is the physical one. The more work you perform in the first creation the easier is the second one. Project development is the first creation of the project and the it is perfected the easier is the project management phase.