"I will paste a sheet of paper."
I'm not on the Japanese section anymore because I tested out of the whole class when they first offered it... But I've been thinking about this, and I realized I don't think there is a literal translation for paste (as a verb)... はる means to stick on, and to paste would be understood through context...maybe
That may be because this is an incomplete sentence. Paste means to attach or stick something TO something else. In this sentence, we have no idea what this paper is being attached to exactly. At a post office, you could write your name on a piece of paper, then stick/paste/glue/tape/attach the paper to a box.