Desmume is the best for LP, but it will take some tweaking.
You might wish to use an older single or dual core pc, as emulators can only utilise one core it may be too slow. Another way is to use a virtual machine, but that is a LOT of messing around and depending on the architecture it may be too slow to play. My single core 3.4 and dual core 2.8 run it better than my multi core AMD A8. (5x1.8ghz cores with overclock up to 2.5)
Love plus, Love plus +, New Love Plus +, LovePlus on Android/Gree and Love plus IR. Now playing NLP+ happily on my Rinko deluxe 3DS LL 3DS: JP 3DS LL - 11.4.0-37J LUMA & B9S & HBL
Can I Ask Something? I'm Playing Manaka Route Right Now And I'm Stuck At The Dream Event Because It Told Me To Talk Using A Microphone, But SInce I'm Using Desmume n I Don't Have A Microphone Attached To My Laptop, How Am I Going TO Proceed?