I don’t know ______ to value your qualities.

Only how

How

So how

None of these

"Know how" is the correct phrase to indicate understanding a method.

"How to value" correctly expresses the ability to appreciate qualities.

I don’t know how to value your qualities.

میں نہیں جانتا کہ آپ کی خصوصیات کی قدر کیسے کریں۔