assiduously
audaciously
bec et ongles
boldly
bravely
bulldoggishly
chivalrously
committedly
courageously
daringly
decidedly
decisively
determinedly
devotedly
diligently
doggedly
doughtily
earnestly
faithfully
fearlessly
firmly
fixedly
gallantly
gamely
gutsily
hammer and tongs
hardily
heart and soul
heroically
in all seriousness
in earnest
in good earnest
indefatigably
industriously
inflexibly
insistently
intrepidly
knightly
like a bulldog
like a leech
like a man
like a soldier
loyally
obstinately
patiently
perseveringly
persistently
persistingly