What is the best way to share the blockchain and get it verified by the wallet?
You can literally concatenate all the *.dat files and share that. The user downloading can use that as their base download by using the bootstrapping option (-loadblock) in bitcoin core.

Generally, the trust a user puts in the blocks you give them is not really needed since the proof-of-work is verifiable by the new node. New blocks will also reference the previous block so it's easy enough to verify that they're on the chain that new blocks are coming in from.