Things are seldom what they seem

Things are seldom what they seem.

Prov. Things often appear different from what they really are. Emily seems to be a fine young lady, but be careful. Things are seldom what they seem. To judge from his elegant clothing and luxurious car, William was a wealthy man. But things are seldom what they seem; in fact, he was in desperate need of money.
See also: seem, seldom, Thing