What are meanings of "ithni" and "jithni"

'jitne' word is to used discribe, something which has no limit.

And 'itne' word is always used for decribing finite number of thing

Itnaa, Itni and Itney / itnay / itne (whichever way U pronounce is acceptable) = this much.

Muze ek cup itnaa paani chaahiye
itni see baat ke liye gussaa kyu hote ho ?
Unhey itney he aam chaahiye.

Jitnaa / jitni / jjitney - U can use for - that much, upto, as much as, overwhelming etc. etc.
Ex : Jitnaa pyaar aap Mata Pitaa ko day sakate hai, utnaa / ottnaa kam hai.
Jitni bhi mai aapki taarif karu ootni kam hai.
Jitnaa / jitney chaaho utnaa / ootnaa chillla o.

Jitnaa, U can also use as Verb : = to Win