“Appreciate” is a transitive verb and must take an object.
In this sentence, the speaker is appreciating the “saying that,” which, by virtue of its being a gerund and therefore being regarded as a noun, is the object of the verb and not the person who is saying.
So, the second sentence is correct.
In this sentence, the speaker is appreciating the “saying that,” which, by virtue of its being a gerund and therefore being regarded as a noun, is the object of the verb and not the person who is saying.
So, the second sentence is correct.