Long story short, it can be translated as "a son of a bxxch" or "a bxxch." 😂 According to Standard Korean Language Dictionary (표준국어대사전), 간나 is a dialect word used in South Gyeongsang province of South Korea and Hamgyong province of North Korea meaning, "little child" and "girl," respectively. 쉐이 and 쒜이 are altered pronunciation of "새끼," which is vulgarism/slang that can be used as "bxxch," "cxxt" or "nutter" depending on the context ('새끼' itself can be considered offensive or not offensive depending on the context :).) Hope this helps :)!