trustful
Ready to believe others and expect them to be honest.
Trustful means having or showing trust in others, being ready to believe in people's honesty and good intentions. A trustful person tends to take people at their word and expects them to be sincere.
When you're trustful, you give people the benefit of the doubt. A trustful child believes their friend who promises to return a borrowed toy. A trustful teammate relies on others to do their part of a group project without constantly checking up on them.
Being trustful is different from being trusting, though people often use these words interchangeably. Trustful describes someone's attitude or approach in a specific situation, while trusting describes a more permanent quality of someone's character. You might feel trustful toward a new classmate even if you're not naturally a trusting person.