It is 'mon amie'. It should be 'ma', because 'amie' is there a feminine, but for the sake of pronounciation, 'mon' is substituted. (if not, you would have two vowel sounds following each other)
I love you, my friend (female).
Note: The correct spelling is "je t'aime". The given spelling of "j'taime" could be a representation of a quick way of pronouncing it, since it is common for French...
Mon amie is 'my (female) friend', mon ami is 'my (male) friend'. It is mon amie, not ma, because amie starts with a vowel and so it would be more difficult to say. However, if you put an adjective in...