After discovering the powers in him, Hanuman flew to Lanka but faced a massive mountain that requested him to rest for a while and he also met Surasa, a demoness who would not let him pass unless he is eaten by her. Both had the powers to change their size, and as Hanuman changed his size, the demoness increased hers. In the end, Hanuman used his brain and decreased his size to that of a thumb and went in and out of her mouth. This fulfilled the curse of Brahma as well as allowed him to go ahead without any bloodshed.
Surasa later revealed that she was appointed by the Gods to test the strength as well as the intelligence of Hanuman and then blessed him that he would be successful in whatever he does in his life.
Hanuman proceeded to fly towards Lanka. A demoness named Simhika awaited him at the entrance of Lanka. She was the sister of Ravana and was appointed to safeguard Lanka from any intrusion. On seeing Hanuman, she said,
“Wow. What a nice soldier! It is time for me to feast on you, mighty soldier. It has been a long time since I had the chance to eat someone so strong and well built! I cannot wait!”
“If you want to fight, so be it. Let me see how strong and capable you are that you are telling me that you would eat me up.”
They both started fighting. After some time, Hanuman got bored and realized that this is taking too much of his time and he should hurry now to make sure that he reaches Sita on time and conveys the message of Rama. Hence, he wasted no time and killed Simhika immediately with his mace. Simhika could not even realize what happened and she was dead in no time. Hanuman went ahead.
He flew over the Lanka and realized that Sita was kept in a garden where there were many guard women guarding her and she could not escape. Hanuman quickly changed his size to that of a fly and went and sat on a tree near Sita. As soon as he got a chance, he revealed his true form and approached Sita.
“O Mother Sita, I am Hanuman and I am sent by Rama and he has told me to convey a message to you with this ring. He would soon be here and rescue you from the hand of Ravana. Please be patient.“
“Oh messenger, I am sceptical of everyone and I cannot believe you until you show me the ring. Please show me the ring and I would only believe you then. There are so many illusionists here that trust is a rare phenomenon to have here.”
Hanuman immediately shows her the ring and gives it to her. Sita immediately recognised the ring. She was overjoyed to know that she is soon going to be rescued by her husband. She says,
“Oh Hanuman, I do believe you now and you may go and tell Rama that I shall eagerly wait for his arrival and for him to rescue me from this demon!”