Factual error: Marianne quotes Hartley Coleridge's Sonnet VII to Elinor ("Is love a fancy or a feeling?") to inquire about her feelings for Edward. However, this sonnet was published for the first time in 1833 - some 22 years after Sense & Sensibility takes place in 1811.
Continuity mistake: Toward the end of the film, Elinor is gardening and has dirt and mud all over her hands. Upon realising Edward is riding toward the house, she hurriedly wipes her hands on her apron, smearing a good amount of dirt on it. When she then removes the apron while standing inside the house, both the apron and her hands are barely dirty.
Continuity mistake: In the scene where Lucy Steele admits to Fanny Dashwood that she is secretly engaged to Edward, Lucy starts the scene holding a lapdog. When Fanny explodes and attacks Lucy, the dog has disappeared from the set.
Factual error: The roads show only two wheel tracks, there is no wear on the center of the road, from either horses or oxen. Most pre-auto movies miss this.
Factual error: Elinor mentions the Russian city of Vladivostok. However, Vladivostok was founded in the late 19th century, several decades after this movie was set.
Answer: The lyrics come from a poem called "Weep You No More, Sad Fountains" - it was set to music specifically for the film by Patrick Doyle. There is sheet music available for this piece here: http://www.sheetmusicplus.com/title/selections-from-sense-and-sensibility-sheet-music/2923004. As far as I know, you have to buy both 'The Dreame' and 'Weep You No More Sad Fountains', but they are both here.
Tailkinker ★