"This child wants to go."
Translation:यह बच्चा जाना चाहता है।
चाहता is the main verb which corresponds to 'want'. However, all present-tense sentences in Hindi have है as an auxiliary verb to indicate that they are in fact in the present tense. This है can only be dropped in negative sentences.
So, 'यह बच्चा जाना चाहता' is not a complete sentence without है.