"this is love"? i don't think its a single.
her single was (if you're talking about actual single cd and not the songs then)

automatic/time will tell
moving on without you
first love
addicted to you
wait and see risk
wait and see nisuku
for you/time limit
can you keep a secret?
final distance
traveling
hikari
sakura drops
colors
you make me want to be a man
be my last
passion
Dareka no Negai ga Kanau Koro
flavor of life
beautiful world
keep tryin
boku wa kuma
flavor of life
easy breezy
devil inside
exodus
and heart station :D

but i think thats all of it....anyone else can prove me wrong. :D