What does “vouloir dire” mean in French?

French has a formal verb for “to mean” — signifier — but speech reaches for vouloir dire, literally “to want to say.” Qu’est-ce que ça veut dire ? is the question worth having ready: “what does that mean?” And ça veut dire que… introduces a conclusion you are drawing. The subject is normally the thing doing the meaning — a word, a sign, a fact — rather than the person.

Put a person in the subject slot and the sense shifts to intention: je voulais dire is “I meant (to say),” and tu veux dire que… is “you mean that…”, used to check you have followed someone. For “I mean it” in the sense of sincerity, French goes elsewhere entirely: je le pense vraiment.