How do you say i miss you in Swahili?

I miss you = Nimekumiss (which is informal)

Note:

Everyone in East Africa understands nakumiss, often spelled nakumic, as "I miss you" or tunakumiss or tunakumic, we miss you. The supposedly formal verb kutamani is NEVER used in this sense, and this contributor warns anyone against so using it. It will be understand as "I want you" in a sexual sense or "I lust for you."