What do we say in English no. 16

Dear All,

Here's the situation: person A offers something to person B. Person B hesitates and in the meantime person C comes along and is willing to take person A's offer. Person A goes to person B and says: "There's another person interested in my offer but you were first on my list and I asked you first so I'd like to know your final decision"

Now, how would we say thank you to this person?

Thank you for being considerate and sticking to your word?

I want to stress the fact that I'm thankful this person has actually thought about me even though she had someone else interested in her offer.

Thanks