Yadira is simply a Latin American respelling of Jadira, which is the feminine form of the Arabic male name Jadir. According to
Muslim & Parsi Names by Maneka Gandhi and Ozair
Husain, Jadir means "worthy, suitable, fit, proper" in Arabic.
In Latin American Spanish it is very common for parents to respell names that start with J- in English with an initial Y-. One can easily find examples of Hispanic American girls with names like Yessica, Yoselin, and Yaneth, which are simply respellings of
Jessica,
Jocelyn, and
Janet. Sometimes these names seem to be pronounced with the English "J" sound by those who bear them and sometimes they are said with English consonantal "Y"; there doesn't seem to be a consensus on that as far as I can determine. So I suspect that some bearers of the name
Yadira say "Yah-deer-ah" and others say "Jah-deer-ah".