Is the opening line true in Pride and Prejudice?
The opening line of Pride and Prejudice is "It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife." Your question is plainly opinion-based, and therefore can be answered in multiple ways. If you have read the story in its entirety, I would recommend trying to support your response with evidence from the text. For instance, you could discuss Darcy's lack of energy in pursuing anyone, and his odd method of engaging Elizabeth Bennet. Textual evidence which supports this statement includes the sentence which follows, which also indicates Austen's opinion of society at the time:
However little known the feelings or views of such a man may be on his first entering a neighbourhood, this truth is so well fixed in the minds of the surrounding families, that he is considered as the rightful property of some one or other of their daughters.
This line is delivered with irony, for which Austen is well known. For instance, deeming a man "property" of a woman ("some one or other of their daughters") was obviously sacrilegious for the time period (during which women were considered property). This line supports her initial supposition in that all of society is aware of the stakes and expectations--everyone knows a man with money should desire to be married.
If you have not read the text and you are being asked to evaluate the truth of this statement, I would recommend in-depth consideration of the social expectations of the setting. Despite the ironic nature of the statement, men of money were expected to marry, and based on historic information alone, you could argue in favor of the statement.
If you are not expected to consider the historical time period, you could argue for or against it based on opinion alone. Whatever you do, I would recommend making connections of some nature--to pop culture, other novels, or personal experiences--to have support for your response.