。
Don't confuse desire with love.
Literal
Desire [object-を] love [with-と] confuse-[negative-imperative-な].
混同する ('to confuse / conflate [two things]') takes を for one thing and と for the other — 'mix up X with Y.' 欲望 ('desire') is a Sino-Japanese compound 欲 ('want') + 望 ('hope / aspiration'). The negative imperative な gives a forceful 'don't.'