“Does Calvinism Offer a Basis for the Assurance of Salvation?”
No.
Can you elaborate?
The only calvinist I know was arrested 6 years ago for child porn. The ugliest kind.
The only Jehovah witness I know had 6 kids, 5 by different men all while married to my Navy friend. She ended up dead. Murdered by a lover in a love triangle, er, love rectangle rather.
So, christian labels mean nothing and are no measure of devotedness.