Regina, Saskatchewan; Canada
I think it has to do with a few things such as blood, blushing, heartbeat, etc increasing and responding to a strong feeling, and the importance of the heart to blood, by analogy being important to a strong affection such as love, as well.
In Hebrew the aph "nose" is associated with anger. There are quite a few places in the bible where literally "nose" is used for "anger", but the translators don't use "nose" in English, because the English speakers wouldn't think "anger". The connection here is from the clenching of the nose, flaring nostrils, or redness of the nose when someone feels anger.
[This message has been edited by Essorant (07-25-2009 02:53 PM).]