Well, if you trust the person that much then go for it, however you never know what people turn into only after a few months.
I am a very "safe" person, so I would rather have my own account. That way I know exactly what goes on with it.
Finance is a very particular thing and fights over money often hurt couples, regardless of where you are in the world. Money disappears, "ohh, you are spending all my money", "ohhh where did our money go this month"...I have no patience with that kind of thing. What if the person disappears with my money one sweet day?
Good luck, I would NEVER trust anyone (except my parents) to have a bank account with me.