promise someone the moon
US /ˈprɑmɪs ˈsʌmˌwʌn ðə mun/
UK /ˈprɑmɪs ˈsʌmˌwʌn ðə mun/

1.
prometer la luna a alguien, hacer promesas imposibles
to make extravagant or impossible promises to someone
:
•
He's always trying to promise someone the moon to get what he wants, but he never delivers.
Siempre intenta prometer la luna a alguien para conseguir lo que quiere, pero nunca cumple.
•
Don't believe him, he's just trying to promise you the moon to get your vote.
No le creas, solo está tratando de prometerte la luna para conseguir tu voto.