The phrase cold hands warm heart is used to describe a person who does not show his feelings explicitly, might even come off as cold, but is very warm and kind and caring on the inside.
You can say this about a person that does not seem like sentimental one, but his actions suggest that they care much about emotions and feelings of other people.
Cold hands warm heart does not have an exact origin story, it has been around for years and its meaning is fairly clear.
Furthermore, it is similar to the phrase don’t judge a book by its cover.
There is also a German phrase, “kalte hand, warmes herz”, which means the same as cold hands warm heart.
Some people believe that this suggests the expression might have originated from Germany.
Cold hands warm heart is a common saying among people.
The phrase inspired lots of artist, several songs have their title named after this phrase, for example: Brendan Benson – Cold Hands (Warm Heart), or the same song title from the band called Strange Ranger.