This is the 17753rd most frequent Russian word.
укрепилась
"Укрепилась" means "strengthened" or "became stronger."
In this sentence, 'укрепилась' is used to indicate the growth or improvement in the country's economic stability, i.e., its strengthening.
Экономика страны значительно укрепилась за последние годы.
The country's economy has significantly strengthened over the past years.
Here, 'укрепилась' conveys the enhancement or strengthening of her physical state due to consistent exercise.
После регулярных тренировок её физическая форма укрепилась.
After regular training, her physical condition improved.
'Укрепилась' in this instance highlights the solidification or strengthening of the friendship between the nations due to cultural ties.