Question

how did Hanuman regain his confidence

Answer 1

Because of the boons he received and the strength which he gained from them, Hanuman was replete with his own speed, like the ocean. Overflowing with energy, Hanuman fearlessly desecrated the hermitages of great sages. He broke the sacrificial laddles and vessels, interrupted the offering of oblations into sacrificial fires and tore up the piles of bark cloth belonging to the peaceful sages. The mighty Hanuman continued doing such deeds. Knowing that Brahma had made him invulnerable to punishment by brahmanas, the sages tolerated it because of his power.