1、“We are besties” - This sounds very young. It might be used by teenage girls to talk about their best friends. 她是我最好的朋友。  2、“We’re attached at the hip” - This sounds cute and it means that you are very close and that you do everything together, it could also be used for a relationship. 我们形影不离／我们是死党。  3、“We are two peas in a pod” - This sounds cute and could also mean that you are in a romantic relationship with the person. 我俩特别像。 4、“We’re best buds” - This also sounds kind of young and it might be used to refer to a childhood best friend. 我们是发小。 5、“We’re super close” – Maybe you would use this if you didn’t want to say “best.” 我们是非常要好的朋友。 6、He／She is my confidant. 他／她是我的知己。 本文来源：https://www.wddqw.com/doc/c4490e3adf80d4d8d15abe23482fb4daa58d1d00.html