"You are happy."
How shall i know if that is singular or plural. Because if it is singular it should be "iksa" or am i wrong here?
If you mean that the English sentence can be translated as both singular and plural, then that is correct. If it says it's incorrect you should report it. The second person singular is indeed iksā.
Yeah Iksat is plural you and iksa in singular. But also kirini is the plural version of happy and kirine is the singular. (sorry about the lack of accents.)