You want to ensure the source and the display are both in UTF-8, and also everything that touches the data is set in UTF-8.
Start from what you are most certain about: Check the DB encoding. You can set a server wide encoding, a database encoding, a table encoding and a column encoding
Next, check the php that handles it The .php source file itself should be in UTF-8, the header and contentype charset etc should all be set to UTF-8.
If you sent the data to somewhere else like a javascript or other php pages for processing, you need to check them all as well. Be careful of any external library, or stream reader/writer, which encoding cannot be controlled by you. The connection you make with the DB may also alter the encoding.
Once you are sure the output is in UTF-8 you need to make sure the browser is displaying in UTF-8. You need to tell the browser what encoding this webpage is in, the browser read that in the header definition.
Good luck!