What is the difference between Liebe Güte and ach je? Both are translated as oh god or similar to that. So I never heard it before from any German. What do they mean and in which context can we use them?
Liebe Güte! Exclamation of terror or amazement. Colloquially. The word "Güte" here stands for god (Gott). Mostly used ach du liebe Güte or ach du meine Güte as phrase unpleasant surprise.
Ach je expresses regret or terror. Example: „Ach je, das tut mir leid“ (What‘s the matter with that).
I hope that clarifies your question
In addition to what SwissCodeMen said: Ach du meine Güte can be a reaction to pure horror news. But if the news are not e. g. life threatening horror, the exclamation can also have the connotation of - more or less suppressed - amusement.
When e. g. it's about someone you have sympathy for and you feel sorry for; but at the same time there is also an entertaining amusing aspect in it that makes you suppress a smirk. => Ach je / Ach du meine Güte = also as reaction to a tragical yet also comical/gossip-worthy situation
In this case: Ach je as a less strong expression, demonstrates a more calm reaction, resignated or matter-of-fact (think of it as the follow-up of a sigh) Ach du meine Güte demonstrates a more lively mood, and indicates the speaker's clear sympathy for but also his mild amusement about the person in question.