IPA: /ˈdʒɛn.ə.rəs.nəs/
KK: /ˈdʒɛnərəsnəs/
The quality of being willing to give more of something, such as money or time, than is strictly necessary or expected.
Her generousness was evident when she donated a large sum to the charity.
Generousness is formed from "generous" (from Latin *generosus*, meaning noble or of noble birth) and the suffix "-ness" (meaning the state or quality of). The word "generousness" refers to the quality of being noble or giving freely.
Think of 'nobility' ('generous') and remember that 'generousness' means the quality of being noble and giving.