"We love you"
Yeah, as RomanMesza said.
Tunawapenda would ordinarily mean "we love them".
To make it clear that it's "you" (plural) the following options can be used.
Tunawapenda nyinyi/ninyi (also fairly common)
Tunakupendeni (dialectal, I think)
I also saw somewhere that in Kenya, -mu- is used, so tunamupenda but I've never seen this, and also it seems strange to me because a lot of people hardly or don't distinguish "mu" from the syllabic "m" (particularly in Kenya, I think), so this could very easily be confused with "we love her/him".
As is being discussed here(though you may not have seen it) the suffix -eni goes to the end of a word with a second person plural object infix. The reason is to distinguish it from the third person plural which also has the object infix -wa- Tunawapendeni - I love you(all) Tunawapenda - I love them