Mike may know where his wife is from, but the sentence is talking about Sam.. :-)
On a more serious note. There could be a few situations in which you might say the above sentence.
e.g. Sam just said "I don't like Jordanians". You say very quietly "Your wife is Jordanian, Sam".
You keep getting it wrong because you are still learning the grammar. That's okay.
English learners also do not understand sentences like "My heart bursts with pride", or "She was walking on air", or "Child is the father of man"... But they eventually understand the grammar. :-)
Sam is a man. If we follow Standard Arabic, it should be زَوْجَتُكَ "zaujatuka" - (1) تُ -tu because the phrase is in the nominative case (as the subject), and (2) كَ -ka because Sam is 2nd-person masc. sing.
In Duolingo Arabic style, "zauwjatik" means "your wife" (to a female) while "zawjatak" means "your wife" (to a male). So, it should be not "zauwjatik".