Mazo de la Roche 
Mary Wakefield [PDF ebook] 

First published in 1949, in Mary Wakefield, the third book in the Jalna series, a young English woman is hired by Ernest Whiteoak to be a governess to Philip’s motherless children. When Philip falls in love with her, his mother does all she can to prevent the marriage. This is book 3 of 16 in The Whiteoak Chronicles. It is followed by Young Renny.