Pain during intercourse in your wife should first be properly evaluated because it can be due to vaginal dryness, infection, vaginismus, hormonal changes, or psychological causes. Using a local anesthetic like Lignocaine (LOX 2%) is not a good first solution for her pain, because it only numbs sensation temporarily and may mask an underlying problem; side effects can include burning, irritation, reduced sensation, and in rare cases allergic reactions. It is better she consult a gynecologist for proper diagnosis and treatment such as lubricants, vaginal moisturizers, or specific therapy depending on the cause. In some cases, counseling or treatment for anxiety or erectile dysfunction is also needed. A joint consultation with a urologist/sexologist and gynecologist is ideal for both of you.