Pokèmon Omega Ruby and Alpha Sapphire: How To Get Heart Scales Easily.
Not the fastest, but it is efficient and easy.
~ZacMazter
Step 1. Thief from Slateport.
Step 2. Super Rod from Mossdeep City.
Step 3. Route 128 catch Luvdisc using super rod.
Step 4. Use the app that allows you to search for Pokemon to find Luvdisc holding heart scales.
Step 5. Attack Luvdisc with thief remove item stolen from Luvdisc.