With experience. When the Borg destroyed my world, my people were scattered throughout the...

Guinan:
[while the Enterprise is concealed inside a nebula, Picard is touring the ship the night before they engage a Borg vessel, and he's now taking a look around Ten-Forward]
Trouble sleeping? Capt. Picard:
[surprised by Guinan's presence]
It's something of a tradition, Guinan. A Captain touring the ship before a battle. Guinan:
Oh, before a hopeless battle, if I remember the tradition correctly. Capt. Picard:
Not necessarily. Nelson toured the HMS Victory before Trafalgar. Guinan:
Yes, but Nelson never returned from Trafalgar, did he? Capt. Picard:
No, but the battle was won. Guinan:
Do you expect this battle to be won? Capt. Picard:
We may yet prevail. That's a... a conceit, but it's a healthy one. I wonder if the Emperor Honorious watching the Visigoths coming over the Seventh Hill truly realised that the Roman Empire was about to fall? This is just another page in history, isn't it? Will this be the end of our civilisation? Turn the page. Guinan:
[smiles]
This isn't the end. Capt. Picard:
You say that with remarkable assuredness. Guinan:
With experience. When the Borg destroyed my world, my people were scattered throughout the universe. We survived... as will humanity survive. As long as there's a handful of you to keep the spirit alive, you will prevail... even if it takes a millennium