Shlomo Hamelech said a Chochom is one who learns mikol odom from everyone. We must just be careful and consider which are the worthy traits of an otherwise bad person that are fitting for us to emulate and which are the aspects of even a good person which need ignoring.
The ‘Mother Teressa’ aspects of Diana’s life including establishing the first treaty against the use of land mines and helping the sick and poor are fantastic achievements worthy of praise. The adultery aspects, amongst others, are the reason we say shelo asani goy, refering even to ‘worthy’ gentiles who nevertheless live a torahless life.
BTW The way you misspelt her name she sounds like a “n na nach”. I suppose she did go around cheering people up…