The prefix part of the word dismayed is 'dis-'. If the prefix is 'un-' it means the opposite of dismayed; not dismayed: undismayed.
Gladdened.
Glad, Overjoyed, Joyous, Happy,
UNfreeze
Hypo is the opposite of the prefix hyper.
The prefix un- makes the word "unsuitable."
The prefix added to "payment" to make it opposite is "non-."
Gladdened.
The prefix added to the word "approve" to make it its opposite is "dis-", resulting in the word "disapprove."
The prefix that would make "bolt" an opposite word is "un-". So, "unbolt" would be the opposite of "bolt".
Glad, Overjoyed, Joyous, Happy,
Im- is the correct prefix. This would make the word immature.
Dis-comfort
The prefix added to "justice" to make it the opposite is "in-". This forms the word "injustice," meaning the lack of fairness or a violation of rights.
The opposite prefix of the prefix "meta-" is "pre-".
The prefix "un-" can be added to the word "incredible" to create the opposite, which would be "uncredible" meaning not credible or believable.
UNfreeze
The opposite prefix for personal is "impersonal."