Depends. Turns out that this is another common sex stereotype–men always state conclusions firmly while women always hedge and dither–that does not truly reflect behavior.
What makes people dithery is perceived lack of expertise when the topic under discussion is associated more with one gender than the other, according to researchers. Some topics cause women to communicate tentatively when the topic is “masculine”–like changing a tire–and firmly when it is “feminine”–like cosmetics. And vice-versa. And with some gender-neutral topics, like picking a good restaurant, both women and men appear equally tentative.