Lyric discussion by evergettheurge 

Cover art for Sanguine lyrics by Avett Brothers, The

I think that this is about the end of a relationship.

Sanguine means cheerfully optimistic, hopeful, or confident. It also refers to being the color of blood, but that is probably irrelevant.

I think that he wants her to tell him that it will be ok, or he wants her to at least let him down gently.

beautiful and melancholy song.

I think you nailed it.

You're actually right on in mentioning that sanguine means the color of blood. In medieval times, blood was thought to be responsible for optimism.