( I want you to work harder.( correct the mistake)
I see it fine.
What about you?
I agree with you.
Verb + Object + to-infinitive
tell, remind, force, enable, teach, order, warn, invite, persuade, get etc.
- I want you to work harder.
Having done a search under the above sentence + 'exam questions', I came across with a similar sentence, and when given the complete example, the mistake becomes evident:
I want you to work harder (than last term just from the beginning.)