To say "I love you" in Zambian languages, you'll need to specify which language you want to know.
Here are some examples:
* Bemba: Ndimukonda (for a male) or Ndimukonda (for a female)
* Nyanja: Ndikukonda (for both male and female)
* Lozi: Ndi ku rata (for both male and female)
It's always best to double-check with a native speaker of the specific language you're interested in.