guarded
v.v. careful about what you say or do because you do not want to reveal too much. You act this way when you do not fully trust someone or a situation yet.
v. cautious and reserved in speech or behavior; unwilling to provide information or show true feelings. Often used to describe a person's reaction to questioning or a medical prognosis that remains uncertain.
He gave a guarded answer to the reporter's personal question.
The doctor was guarded about the patient's recovery, noting that the next twenty-four hours would be critical.
Despite the initial success of the peace talks, both delegations remained guarded, fearing that any premature celebration might undermine the delicate trust they had built.
Often follows a linking verb like 'remain', 'seem', or 'stay'. Frequently paired with the preposition 'about'.