This is the 98th most frequent Hebrew word.
שזה
The Hebrew word "שזה" means "that this" or "that it."
In this sentence, 'שזה' serves as a conjunction linking the clause 'I am glad' with the explanation of what makes the speaker glad, i.e., 'this happened.'
אני שמח שזה קרה.
I am glad that this happened.
Here, 'שזה' connects the phrase 'It is important to know' to the statement 'this is not always so,' providing a reason or a fact to consider.
חשוב לדעת שזה לא תמיד כך.
It is important to know that this is not always so.
In this context, 'שזה' links the imperative 'Remember' to a potential outcome or possibility, 'this can improve.'