Hey @DanielleTiongso!
The unfortunate reality is even if there is a way to require watching the full video, it doesn't mean that students are going to watch it. They can just as easily start a video, walk away, and come back once the video is over. While @Chris_Hofer has a great idea about the insights in Studio, have you considered using the Stimulus option in New Quizzes? You can add the video you want students to watch as the stimulus part of the question. Then add as many questions as you would like that can only be answered by watching the video. Since the video would be the stimulus, it would be on the screen the entire time while the questions could be scrolled through as needed.
How do I insert stimulus content in New Quizzes?
This method is not perfect either since students could share answers, but it may encourage a few more students watch the video, especially if there was a grade associated with watching the video. (If you do not want the quiz to count as a grade, you can always set it for 0 points in the editing window.)
Just a thought.