Sentence examples for must sure from inspiring English sources

The phrase "must sure" is grammatically correct and is commonly used in written English.
It is typically used to express a strong belief or conviction about something. For example, "I must sure that I locked the door before leaving the house" or "He must sure that he will win the race." Here is an example sentence where "must sure" is used: "I am must sure that I studied for the test, but I still feel nervous about it." This sentence conveys the idea that the person is very confident in their preparation for the test, despite feeling nervous.