Mandalay, can you tell what it means to say 'mwen fè kwa'. A Haitian parent asked her daughter to say this after the child was punished. Now i know it means 'I make cross', but is there a deeper meaning to it?

Yes, it does literally say to make or draw a cross.

Some Haitian parents, after they're done disciplining a child, will ask them to say, Mwen fè kwa mwen p'ap janm fè sa ankò.  So here, fè kwa would mean to swear, to vow, to promise 

The parent would say,
Fè kwa.  or 
Fè kwa ou p'ap janm fè sa ankò.
Swear you'll never do that again.

And the child would say, 
Mwen fè kwa m'p'ap janm fè sa ankò. 
I swear I'll never to that again

Other parents would just ask the child to say,
padon! or 
M mande'w padon !
I'm sorry!

Grown ups also use this expression when they vow never to do something.
Examples:
Mwen fè kwa m'pap janm mete pye lakay Betty.
I swear I'll never set foot in Betty's house.

Depi lè papa'l te mouri ak kansè poumon an, li te fè kwa li p'ap janm fimen ankò.
Since the time his dad died of lung cancer, he swore never to smoke again.

Depi lè li te fè aksidan machin nan, li te fè kwa pou li pa't janm monte machin ankò.
Since the time he got into a car accident, he swore never to get into another car.
Sometimes we use prep. 'pou' after this expression.

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words