Use the correct form of the words in brackets

Use the correct form of the words in brackets:
1. Good friendship should be based on ___________ understanding. (mutually)
2. Jane showed great __________ for the new project. (enthusiastic)
3. His strange behavior made the police __________. (suspicion)
4. A __________ is a person with whom one has a deeper relationship. (friendly)
Why are _________ and uncertain people incapable of true friendship? (change