Appearance is often different from reality. Appearance can be deceiving and it will only be as close to reality as how truthful the person is. Therefore, judging a person based on his or her looks is not entirely accurate. In 'The Merchant of Venice', Bassanio is an example of a character with a deceiving appearance. His love towards Portia appears to be true and sincere, but his true intention for going after Portia was only because of her wealth. First impression usually leaves the greatest impact on people, hence leading them to trust a person based on the appearance.
In reality, people also make use of their appearance as a facade to hide their true intentions. 'Backstabbers' are people who appears to be kind and nice in front of everyone else, but will betray friendships to benefit from it. It is all right to form impressions of people based on their appearances but these impressions should not be taken too seriously because it takes time to understand another party. To find out if the party is really true to you, you have to observe - how he or she behave behind everybody's back.
People are still misled by appearance. Stereotypes and prejudice thinking are often created against another person's characteristics - skin colour, body build, gender and others. Portia, in 'The Merchant of Venice', had judged her suitors based on their appearances, even when a fine gentleman like Prince of Morocco asked for her hand, she had rejected him in the first place because of his skin colour.
Appearance is not definite because they are just a rehearsed show, prepared to amaze or even deceive. Reality reveals the curtains behind these shows, showing the true character of a being.