Harry - You never told him you weren't entirely muggle-born. Your father was a squib.
Ron - He was your first and only boyfriend.
Fred/George - You are amazing at qudditch. You only didn't join because you did not want to play with him on the opposite team.
Cedric - You're an adopted child.
Draco - Your parents worked for Voldemort.
Neville - Once, in your 4th year, you took Neville's toad away and kept him missing for 3 months.
They do come to know your secret at one point or another, but he still likes you :)
-RavenMalfoy♡