I want to say if you watch this movie "It makes you happy" or "It makes you be happy". Which one is better ? I don't want to use this part "if you watch this movie".
Use either one of these:
It makes you happy.
It makes you feel happy.
I think "feel happy" sounds more natural than "be happy." We often use "feel «emotion»" when talking about how our feelings might sway because of music we hear, art we see, or programs we watch.
This song makes me feel sad.
That painting makes me feel calm.
That comedy helps me feel silly.
The feel isn't necessary, but I think it sounds better than "be «emotion»" in most contexts.
Is it a movie that your friend has seen before?
If it's a movie that they've seen before and you know it makes them happy, feel free to remark:
This movie makes you happy.
You really enjoy this movie, don't you?
But if it's a movie they haven't seen before and you are merely stating what effect you think it'll have on them, I'd recommend a future construction:
It'll make you happy.
This is going to make you happy.
You'll enjoy this.
You'll love this.
Alternatively, if you are using "you" as an impersonal pronoun and your intended meaning is that the movie "makes people (in general) happy", then I'd say:
This movie tends to make people happy.
This is a very enjoyable movie.
It's a feel-good movie.