The Tosefta in Peah (4:17) states that if a person says they will give tzedaka and then gives it, they receive divine reward both for the "saying" and for the "giving." And in a case where the person says they will give, but is not ultimately able to give, they nevertheless receive divine reward for having said that they will (I'm assuming here that the original "saying" was honest, ie the person truly wanted to / planned to give).
Why might this be? What is it about the mitzvah of tzedaka where a person might get divine reward just for saying they will do something, even in a case where they don't ultimately do it?
(I am understanding the case to be where the person did not make an explicit vow or neder to give, which would complicate matters).