Translation: algo dulce
te quiero (Spanish) -> I love you (English)
So sweet. = Tan dulce.
eres dulce
ricura
You can say "Primer grado es dulce" in Spanish. This phrase captures the idea that first grade is sweet or enjoyable.
muy dulce
Ella es dulce.
dulces sueños
frijoles dulces.
There is not exact Spanish equivalent of this. You could say"Mi amorcito" or "Mi corazoncito"
You can start by learning proper grammar:"What is something sweet to say to your boyfriend when he asks why do you like me?"
hola muchacha dulce