Hey Saurabh,
good question indeed!
What do you need to know the answer for? 
Figuring out the resulting number of records from a join operation typically involves to actually perform the matching part of the join.
As the actual values are not required, SAP HANA can avoid the value-dictionary lookup when preparing the final result set. However the matching step (finding matching records in the other table) needs to be done.
Concerning verification: as I assume you are not looking at a trivial amount of data here, the only way to verify this (without knowing the SAP HANA source code) is to apply another join algorithm to the same data, It obviously would help if you know for a fact that this other join algorithm works correctly .
For HANA you could consider moving the tables from column to row store and run your join SQL against that (this wouldn't work for any modeled views as these depend on column store tables).
- Lars