1. 'I'm glad you like it.' is an expression answering praise or the word of likes of the other person.

Question

2. 'I'm glad you like it.' is an expression we can use when we answer praise or the word of likes of the other person.

Are both expression the same and grammatical? Would you correct them, please?

What about the following?
3. When we express our high opinion about a product, we use this expression.

4. We can respond to the praise of the other person using the expression,"How nice of you to say so!"

Answer 1

#1 = "or the word of likes" is a strange phrase. #2 as well.

#3 What comes after "we use this expression...?"

#4 = good.

Question: Why are you using in every case '.....' instead of "......" ?