If in English you have an expression of desire, doubt, or emotion involving two different subjects ("He would like me to be on time"; "they doubt your sister will arrive on time"), always use in French que + a conjugated form of the subjunctive ("Il voudrait que je sois à l'heure"; "Ils doutent que ta soeur arrive à l'heure").

    On the other hand, an expression of desire, doubt, or emotion can be used with an infinitive if the grammatical subject of the two acts is the same. For instance: "He would like to be on time"("Il voudrait être à l'heure"), "They doubt they'll arrive on time" ("Ils doutent d'arriver à l'heure").

    Notice that some expressions of desire, doubt, and emotion require a de before a dependent infinitive. For instance: "Il a peur de conduire la nuit" ("He's afraid of driving at night"), "Nous regrettons de ne pas avoir vu ce film-là" (We're sorry we didn't see that film"), "Est-ce qu'elle sera contente de partir tout de suite?" ("Will she be happy to leave right away?"). However, other such expressions are used (more or less arbitrarily) without de. So: "Do you like driving or flying better?" ("Est-ce que tu aimes mieux aller en voiture ou en avion?).