Premise: Bellemare ( ; ] ) is a common Norman surname, that means "somebody from Bellemare", name of several hamlets in Normandy (± 20). It is also one of the most common family names in Mauricie, Quebec. It is a compound of French "belle" "nice, pretty" and "mare" "mere, lake, pond", Norman word of Old Norse origin "marr" "sea", finally borrowed from Norman by French around 1600 as "pond, puddle".
Hypothesis: Bellemare was borrowed from Norman by French around 1200.