Difference between "double-closing" and "assigning"

[Blaine Baker]

Hi, i was going through some old forums and someone in the comments said...... 

"As far as actually closing on the property, since you're dealing directly with the seller you can either assign the contract, or use a transactional lender to close on the property yourself and immediately resell to your buyer inn a "double closing"."

what is the difference between assigning the contract and double closing? from what i know, double closing is getting the original seller under contract and getting the cash buyer to sign the assignment of purchase and sale agreement and take it to a title company?

[Eliott Elias]

Double closing: you actually close on the property in your name and sign a contract with your end buyer before you close to close with them again. (more closing costs) 

Assignment: you have assignee sign a assignment of contract with non-refundable earnest money in hopes they will close. 

Double closing ensures you will 100% close