The Spanish cara (“head”) comes from the same Latin word (cara), also meaning the same, “head.”
From that Latin, we get the English cheer (via French’s chere). Thus, the ch‑r of cheer maps to the c‑r of cara.
A face — after all — is the most human instead to make us thankful (to cheers a toast!) for life. And most faces fill us with enough happiness to make us cheerful!