Correct spelling, explanation: the word rendezvous comes from French, that’s why its structure reminds us of this language. When writing down this noun/verb, we must bear in mind its origin and etymology. We can clearly see that it contains the -z letter. Keeping this in mind, we will not make a spelling mistake. Rendevous is not correct.

Definition of rendezvous:
1. noun, a meeting or date
I can’t see you tonight. I’m planning a little rendezvous with my boyfriend.
Our rendezvous will take place in a restaurant.
2. verb, to meet someone, especially secretly, at a particular place and time
Maria and Susan rendezvouses with their friends at Warsaw Chopin Airport.
If you want to rendezvous with your father, just go. You don’t have to hide from me.

Collocations with rendezvous:
Some most commonly used collocations include: a place for a rendezvous.
This café is a perfect place for a rendezvous, especially for lovers.
A found a terrific place for a rendezvous! We should go there tomorrow.

Incorrect spelling, explanation: this word cannot be spelled as rendevous, because this version doesn’t match with the French one. Rendezvous is a borrowing, so its construction must accord with the original noun’s construction. It means that you can’t omit any letter. Rendevous is just an error because it lacks the -z consonant. Therefore, you can be sure that rendezvous is the correct version.