YOU SAID:

to fall head over heels for someone

INTO JAPANESE

誰かのために真っ逆さまになる

BACK INTO ENGLISH

go head over heels for someone

INTO JAPANESE

誰かのために全力で取り組む

BACK INTO ENGLISH

work hard for someone

INTO JAPANESE

誰かのために一生懸命働く

BACK INTO ENGLISH

work hard for someone