1. Because there were people here who believed in him.
believe in：信任，信仰
例：
We believe in our government.
我们信赖自己的政府。
I believe in love because my wife taught me how.
我相信爱，因为我妻子教会我如何去爱。
2. George, dear, do hurry.
do：表示强调的语气
例：
Do remember to finish your work!
一定记着完成你的工作！
3. Mrs. Darling believed that Peter Pan was the spirit of youth.
spirit：精灵，灵魂
例：
She did not turn into foam. She became a spirit of the air and was happy at last.
她没有变成泡沫，她变成了空气中的精灵，最后得到了幸福。
They believe that his spirit lives on after death.
他们相信他死后灵魂还活着。
4. Well, Mr. Darling was a practical man.
practical：实际的，现实的
例：
There are plenty of practical obstacles.
现实存在着大量障碍。
So this practice was not very practical for ordinary people.
因此，这种尝试对普通人来说不太实际。