dissemble, disassemble

Dissemble or dissemble means to conceal one's feelings or intentions--
She tried to dissemble affection and warmth, but she loathed them all.
She tried to dissemble nonchalance, but she was crazy about him.
Was she clever enough to dissemble, and fool them all?

Disassemble or disassemble means to take apart--
We may need to disassemble the table to get it through the door.
You can disassemble the unit, making it easy to move or store.

Now that you know that, you can say--
"She forced herself to dissemble cheerfulness, although she was angry that he broke the clock when he tried to disassemble it."

Note--"Dissemble" is a verb ( action word ), with all of the usual verb forms--
I dissemble; you dissemble; he dissembles.
Yesterday we dissembled; we will be dissembling tomorrow.
Note # 2--"Disassemble" is also a verb, with all of the usual verb forms--
I disassemble; you disassemble; he disassembles.
We disassembled yesterday; tomorrow we will be disassembling.