you can write to each other. You can get to know each other by learning from friends and family of the guy. Talking to his sister. asking your brother to hang out with him. Or from a chaperoned conversation. Or see how they interact with others.
He is not having a sis and I aint have a bro :P so no possibility.. I just have a lil fear how he will act or react after marriage. Will he be able to understand me or me him. After marriage I want to always stay confident and dont want to get afraid of anyone neither my hubby nor my in-laws, respect is always there for them :)