Saints are not perfect individuals who always make the right choice every single time. In reality, saints are those who recognize their own faults and continually strive to be holy, even though they often fall short.
Here is a prayer composed by St. Thérèse of Lisieux that recognizes this reality. She lived a holy life, but she wasn't perfect. She would sometimes fall, but what made her unique was her complete trust in God. Even when she fell, she knew that God would pick her back up.