help please

Can anyone identify which Dickens novel the following German quotation comes from or even translate it into 'Dickens English', please?

Fröhlichkeit und Zufriedenheit sind
vortreffliche Schönheitsmittel. Sie
bewahren dem, der sie besitzt, das
jugendliche Aussehen.
Charles Dickens

Thanks

Christine

Roughly, it translates into this:

Joyfulness and satisfaction are
great instruments of beauty. They
preserve, for those who possess them, the
youthful appearance.
Charles Dickens

It may sound vaguely familiar, but I can't relate it to a certain novel, as of now. Maybe Bleak House, but I could be wrong.

I don't really know, sorry, can't help.

Many thanks for your help - it sounds good.