Use of kinda and kind of in fiction [closed]
There are few hard and fast rules for dialogue, since you're trying to capture people's speech. At one time, it was quite common to use a variety of creative misspellings to indicate different dialects. In more recent times, readers tend to find this annoying and potentially offensive.
In this particular case, I think it would be perfectly fine to use "kinda," "kind of" or both as they suit your needs for either dialogue or a first-person narrative (I wouldn't typically use either for writing in the third person). Just remember, even a few of these phonetic renderings tend to go a long way for most modern readers.