When we talk about the .com domain, it is global domain which can be registered by anyone using any of the domain prover like GoDaddy, Bluehost etc. But .com.np domain can be registered only through domain provider called, mercentile communications .
You can register .com.np domain for free but there are certain conditions to get .com.np domain. You need to provide supportive documents to mercentile communications to register .com.np domain. If you want domain of your name you should provide your citizenship documents and if you want domain for your business then you should provide registration documents of your business.
Since .com domain can be registered by anyone without providing proper documents to domain registrar, anyone can register domain and make website as per their wish. Such websites can be operated by anyone. For example, a non medical students can operate website like iamhealthexpertofnepal.com dispite of his knowledge in health sector.
But incase of .com.np domain it is not possible to register domain without having registration certificate of your business. Also, people providing citizenship or passport as supportive documents can only register domain of their name only. For example, if your name is saimon then you can register saimon.com.np domain, if it is not already taken by someone else. So only registered business or person with their own name can register .com.np website which makes it more trustworthy then .com domain.