Gina was uncomfortable in the company

[Bassim]

I am wondering if my sentences are grammatically correct.

Gina was uncomfortable in the company of Peter's parents. They seemed to watch her every move and even counted her mouthfuls. The possibility of them becoming her in-laws gave her trepidation.

 

[emsr2d2]

Just saying "her mouthfuls" isn't clear. You'll need to elaborate. Use something like "counted her mouthfuls of food when they ate together".
"gave her trepidation" is incorrect.

 

[Bassim]

emsr2d2.

I am wondering if I could say instead "make her anxious"?

I was thinking about which verb to use with "trepidation", but I couldn't remember any. Do you have any suggestion which verb could I use with "trepidation" in my sentence?

 

[emsr2d2]

There are lots of verbs you could use if you follow them with "with trepidation". Scroll down to the example sentences HERE.

 

[Bassim]

Does this sentence sounds natural?

The possibility of them becoming her in-laws filled her with trepidation.

 

[Tarheel]

Does this sentence sounds natural?

The possibility of them becoming her in-laws filled her with trepidation.

I would prefer "anxiety" or "dread" in that sentence.

 

[Roman55]

Does this sentence sounds natural?

The possibility of them becoming her in-laws filled her with trepidation.

Yes, it does, and it's what I was going to suggest.