Translation:We open our restaurant only in the evening.
Alternative answer: we only open our restaurant in the evening. Same meaning
No jarrettph, it is not correct. "Night" is לילה, which is different to evening (ערב).
I would normally write מסעדתינו with Yud. In fact, I thought you had to write the Yud, or is it just optional?
With Yud it is a plural "our restaurants", without Yud it is a singular "our restaurant". מסעדתינו versus מסעדתנו.