I cannot pair my LG phone to my Blueant X3 micro bluetooth headset. The phone recognizes it, but doesn't let me pair. During the attempt, I receive "device pairing incomplete" then I am asked to enter a passkey. I enter 1234 and wait, but pairing is unsuccessfull after about a minute.

You have to turn off the Dare's autopairing feature. The Dare was designed to autopair with devices using the 0000 code. The Blueant X3 uses the code 1234 so the autopair won't work.

Once you turn the feature off, start the pairing process all over again and it will work.

Unfortunately you'll have to turn the X3 on through the Dare's bluetooth menu every time you want to use it. You can't use the "on" button on the X3.

1111 or 0000

It sound like the pairing is fine but you have a wrong pin code . Try to turn your blueant off while pairing and turn it back on than try to repair again .
the pairing can be hard if you have various electronic devices close by . try to have radios or any electronic system turned off while paring