Happy Rabbit is not alone
A rabbit is a prey animal that lives in the wild in groups. Your pet rabbit does not live in the wild but he still thinks as a wild rabbit so he needs a friend just to feel safe, among other things. I know you will do whatever you can to protect your bunnyfriend, but to your bunny that is not enough.
Besides, it is great to have a friend that speaks the same language, likes the same games and loves the same food. Of course you give your pet rabbit lots of attention, cuddles and love but who keeps him company when you are at school or at work? And where are you at night, when your rabbit is most active? Probably asleep in your own bed.
Furthermore, rabbits keep each other clean and healthy. Do you wash the ears and eyes of your rabbit? With your tongue? I do not think so. You know for sure your pet rabbit is really happy when he has a rabbit friend and you can see for yourself how they play, walk around, show binkies and sleep closely next to each other.
The best combination is a male and female , where at least the male must be castrated, not just to prevent baby rabbits but also to prevent behaviour problems. Two castrated males or two females as a pair are possibilities but these two combinations are most likely to cause problems. It is better to start with the best combination to prevent you from having to change one of your rabbits later.