Sincere, to be honest and trust worthy.

I think she was being sincere, so I think we can trust her.

Sometimes it's very difficult to know if someone is being sincere, or is just a good liar.

Naive, overly simple and lacking experience.

He wants to change the world, but he's very naive, so he needs someone to help him.

I think we can take advantage of him, because he is naive and impatient.

Brilliant, highly intelligent or?exceptional in brightness, the opposite of dull.

There is no doubt that he is a brilliant scientist, but he is a very poor manager.

It's amazing, how such a brilliant man can be so stupid around women.

Cruel, mean,?manipulative?and hurtful,?The opposite of kind.

He can be cruel when he doesn't like someone, so don't expect him to be nice to you.

I was shocked by how cruel he was?when he fired her.

Clever, innovative, creative, very smart.

He found a?clever?solution?that allowed us?to reduce costs.

Advertisers are very clever at getting people to buy things they don't really need.

Skeptical, needs?proof or evidence to overcome doubts, the opposite of convinced.

I'm sure they will be skeptical of our results, so we need to bring convincing evidence.

I'm skeptical that such a simple design can satisfy our requirements.