This is the 13573rd most frequent Spanish word.
repleto
Full or packed.
Here, 'repleto' describes the backpack as being full or stuffed with books.
Mi mochila está repleta de libros para la escuela.
My backpack is filled with books for school.
In this sentence, 'repleto' is used to describe the restaurant as being fully occupied or crowded with people.
El restaurante estaba repleto de gente anoche.
The restaurant was packed with people last night.
In this case, 'repleto' figuratively indicates that her heart is full of joy, showing a high emotional state.