I don't think it's an actual symbol. Just two ninety degree angles to help with drawing, and a heart on top to represent that it's a love story.
In Japan they call it "love love umbrella" (Ai ai gasa) and it's like if you draw it and write the name of your crush/lover on one side and yours on the other, your love will come true (if it's a crush) or you'll have a nice love life (if it's a lover). Using/shairing the same umbrella is considered romantic in Japan.
Actually it's not an arrow, it's an umbrella ^^ In europe people write the first letter of their names in a heart, in Japan they write their names under an umbrella. And the heart was added to make it more lovey-dovey I guess ^^
By the way there is an umbrella drawn on a wall in Animal Crossing New Leaf 3DS but I never managed to read whose names were written in it XD
Interesting.
What's that arrow heart sign called?
http://www.mangago.zone/read-manga/akihabara_fall_in_love/mh/c004/4/