Sanguine: 1) Having a ruddy (reddish) complexion. 2) Cheerful, hopeful, confident, and optimistic; impulsive.
The word "sanguine" from the Latin "sanguineus" for "blood" has long been used in English for things relating to the blood. A person who is ruddy in complexion is sanguine. His (or her) ruddy countenance was once thought to be due to their having a predominance of one of the four humors -- blood.