The verb चाहना means “to want”, “to wish”, “to desire”.
Typically the verb चाहिए is used in an indirect verb construction to express wanting some thing:
मुझे चावल चाहिए – “I want rice”
However, to express wanting to do something, चाहना is used along with a complementary infinitive. A complementary infinitive complements another verb or verbal; for instance, in English, the phrase “I want” is incomplete. However, “I want to go” is a complete thought – the complementary infinitive “to go” complements the idea of the main verb.
मैं जाना चाहता हूँ – “I want to go”
मैं हिंदी बोलना सीखना चाहता हूँ – “I want to learn to speak Hindi”
In the previous example, two complementary infinitive were used. The first infinitive (बोलना) clarifies सीखना (what the person wants to learn), and the second infinitive (सीखना) clarifies the main verb (what the person wants to do).
When negated, नहीं simply precedes the main verb:
मैं उससे मिलना नहीं चाहती – “I do not want to meet him”
However, note that a complementary infinitive may only be used with चाहना in Hindi when the subject of the main verb and the subject of the complementary verb are the same. Otherwise, Hindi speakers employ a subordinate clause conjoined by the subordinating conjunction कि to express the complementary idea:
मैं चाहता हूँ कि तुम ठीक से पढ़ते हो – “I want you to study properly”
पिता जी चाहते हैं कि मैं घर जाऊँ – “Father wants me to go home”
Note that the verb in the subordinate clause is in the subjunctive mood. This is because the subordinate clause represents a wish.
चाहना can mean “to love”, “to be fond of”, “to like”, etc.
मैं तुझको चाहता हूँ – “I adore you”
मैं अपनी बीवी को बहुत चाहता हूँ – “I adore my wife very much”
सुब लोग तुम्हें बहुत चाहते हैं – “Everyone is very fond of you”