IMPORTANT - When you sell a decoration, you lose the Flowers associated with it and your Flower level will decrease as a result!
To sell a decoration in June's Journey, tap on it. A little pop-up will appear at the bottom of the screen with the information and controls for that item.
Tap on the green money bag button to see how many Coins you can get if you sell it. Tap again on the green Sell button to confirm the sale!
Note that when you sell an item you receive a percentage of the original purchase price of the item back in Coins, even if the item was bought with Diamonds. Buildings and Landmarks cannot be sold.