When Hiccup and Marie enjoyed their kiss... they had a problem.

Marie: Wait! How will tell the others about me? What are you going to do?

Hiccup: oh, yeah... uh...um, ooh I got it! Put your disguise back on! And make your voice go deeper again.

Marie: Yeah! That would work! Great thinking Hiccup.

Hiccup: Thank you...but it will be a secret!

Marie: Okay.

So Marie put her hair back up, made her voice go deeper, back to the man voice she had; And went her way back to the Edge. With Love in her heart, and a secret on her lips.