demand (n) firm request; need/desire for goods/services; [plural] difficult/tiring things you have to do

'My demand was rejected, for it was unreasonable.'

'Reading in Cambodia was increasing, so the high demand for the new genres of books will rise.'

'I was demanded to write a novel within two months. The demand of this job is impossible.'

 idiom:

• by popular demand: because a lot of people have asked for something
• in demand: wanted by a lot of people
• on demand: done or happening whenever somebody asks