To convey an attitude to an action or event being talked about, a speaker can use special words: "должен", "рад", "уверен", "готов", "надо/нужно".
The words "рад", "уверен", "готов" are short forms of adjectives. Thus, they agree with nouns or pronouns in gender and number.
Consider the sentence structure in the following examples:
For example:
BUT!
Я уверен, что видел этот фильм.
Please, remember!