The relationship between former Jedi Padawan Ahsoka Tano and Senator Padmé Amidala was a strong friendship between these two strong women. They grew acquainted with each other, considering each other as friends and met through their affiliation with Anakin Skywalker.
At some point, Ahsoka suspected that Anakin and Padmé were in a secret relationship but chose not to say anything because it was none of her business.
Ahsoka later protected Padmé from an assassin, Aurra Sing, which caused them to grow closer. Padmé later went behind Anakin's back and decided to "teach" Ahsoka about politics by convincing Ahsoka to use her Jedi authorization to travel to the neutral world of Mandalore, where they would sneak onto a transport to take them to a Separatist controlled planet. Ahsoka learned a lot in her journey and that the war isn't as black and white as she thought and Padme smiled, showing she was glad she taught Ahsoka something.
When Ahsoka was accused of bombing the Jedi Temple, Padmé was one of the few who believed in her friend's innocence and agreed to represent her during Ahsoka's trial.