"I know his neighbor Rosa."

Translation: أَعْرِف جارَتهُ روزا.

[tsuj1g1r1]

By the way, أعلم جارته روزا wouldn't work, as علم only applies to pieces of information. So it's like French "savoir" or German "wissen." But معرفة can translate both "savoir/wissen" and "connaître/kennen."

[Mi_amas_Noha]

أعرفُ جارتَهُ روزا