This is the 1404th most frequent Russian word.
восстановить
To restore or recover.
Here, 'восстановить' is used to express the idea of retrieving or restoring something that has been lost.
Я хочу восстановить свою утраченную фотографию.
I want to restore my lost photograph.
'восстановить' in this context signifies mending or recovering a relationship.
После долгой ссоры они смогли восстановить свою дружбу.
After a long argument, they were able to restore their friendship.
The word 'восстановить' here refers to the act of reviving or bringing back to the original state what has been degraded or diminished.