Yes, thats a beautiful story )
Initially Surya didn't want anything for Guru dakshina, but after Hanuman insisted, he asked him 2 things: look over Surya's sun Sugriva and marry Sun's daughter. There were two issues about her: she wanted to dedicate her life to God and remain Brahmachari and she was so bright, that none could look at her or be next to her. So Hanuman was perfect solution ))
These stories are amazing, aren't they )