This is the 9685th most frequent Russian word.
честный
Honest.
Here, 'честным' (chestnym) is used as an adjective to describe 'человеком' (chelovekom), denoting a person who is truthful and adheres to moral principles.
Он всегда был честным человеком.
He has always been an honest person.
In this case, 'честно' (chestno) is used as an adverb modifying 'говоря' (govorya), indicating the manner of speaking with sincerity.
Честно говоря, я не ожидал такого результата.
Honestly speaking, I did not expect such a result.
Here, 'честно' (chestno) is used as an adverb to describe the action 'выиграла' (vyigrala), emphasizing that the victory was achieved in a fair and just manner.