You are happy.
I am trying to work from English to Hindi but when I type the various ways to say "You are happy" it isn't accepting my answer, even if I cut and paste Duo's answer तुम खुश हो. Any suggestions?
Also try 'तुम ख़ुश हो' which uses the letter ख़ that is more technically correct here.
However, in Hindi, ख is used instead of ख़ in most places both in writing and pronunciation so yours should definitely have been accepted. You can also report it so the error is rectified.