Express dynamics, such as entering the house to emphasize the action of coming in, coming in to express coming in, and emphasizing the state;

Cheng has a deep and direct feeling.

Let's look at an example. Look into someone's eyes. It means looking into someone's eyes; Looking at people's faces emphasizes staring, because you can't see each other's faces, not to say that you don't look at each other's faces. Do you just look at the toes under your head when you meet? Looking to the future, emphasizing overlooking. Cheng has a deep and direct feeling in all three sentences.

If you are interested, I recommend you to buy a book on English vocabulary analysis. In these sentences, you don't have to use Into, but there is a certain difference between using into and using in

I hope I can help you.