Described as between friends

朋友不一定合情合理，Friendships need not be able to be reasoned,
但一定知心知意       ；but we need to have each other in our hearts;

不一定形影不离， We need not be seeing each other everyday,
但一定心心相惜； but we definitely value each other's presence;

不一定锦上添花， Friendships may not make our lives prettier,
但一定雪中送炭； but we'll be there when needed;

不一定常常联系， We need not keep in frequent touch,
但一定挂记在心。 but we miss each other every so often.