plomb (lead)
Crouton.
bananabacteriabasilicaballerinabelugabandannabarracudabolognabulimia
Bellybuttons would be the longest word I can think of beginning with a 'b' and ending in an 's'.
Eight letter words beginning with b, ending with e:backsidebaselinebegrudgebelittleblockadeblockagebreakage
Scarab.
thumb
thumb
cherrub
Bewitch
In French, the word "douce" is feminine. This can be determined by looking at the ending of the word, with the "e" at the end indicating it is feminine. In French, nouns and adjectives have gender, with feminine words typically ending in "e" and masculine words often ending in consonants.
I don't know the word itself as a French word, but it must be something to do with happiness (felicite, in French). The 'a' ending almost suggests an Italian word.
bath