Please note that I will try my best to keep major spoilers secret by making them have to be highlighted to be seen. But if your concerned about spoilers then you should really not be looking at a FAQ
How do I get the romancing stones?
1. - Right after your house is burned down, go back into Touvil and you'll
be
able to walk around the ruins. Go to the back right corner of Arc's
house and examine the wall there to find it.
2. - Right after Iga joins your party, go to Touvil and read the letter your
father left in the mailbox for you, the Stone is with that letter. In
case you're unsure as to where the mailbox is, it's the brown thing that
looks like a sign in front of the house.
NOTE: You have a limited time to get this stone. Once you progress the
story to the point where another letter is in the mailbox, the
stone will be gone.
3. - You get this one automatically when Gogen joins.
4. - On Level 50 of the Forbidden Dungeon, it's in the treasure chest that is
nearest to your party at the start of the level. It's also the only
chest that's not on the other side of the divider.
NOTE: You only have one chance to get this, as once you beat Choko, you
will no longer be able to walk around on 50, thus, the chest goes
kaput.