This is the 450th most frequent Hebrew word.
רבה
The Hebrew word "רבה" can mean "increased," "multiplied," or "became many," depending on context.
The word 'רבה' here illustrates the intensity or extent of the conversation ('extensive').
היה לנו חילוקי דעות, ולכן היתה לנו שיחה רבה על הנושא.
We had a disagreement, so we had an extensive conversation on the subject.
In this context, 'רבה' conveys the teacher's level of hard work and commitment ('hard-working').
בגן הילדים עובדת גננת רבה ומסורה.
A hard-working and dedicated kindergarten teacher works in the kindergarten.
'רבה' is used to emphasize the greatness of the surprise ('immense').