Is the rotator cuff repair a risky thing to do?

No. Rotator cuff surgery is fairly routine. The one exception may be the chronic masive tear which can be very challenging to fix and in some cases impossible. Your best bet for a successful outcome is chosing a surgeon who routinely performs cuff repairs.
No. Anytime you have surgery, there are risks. Prior to surgery you should see your primary care physician for evaluation, to ensure your heart and lungs are healthy enough for surgery. Assuming everything is ok for surgery, there is a chance for bleeding, infection, pain, nerve damage and failure of repair after surgery. These risks are very small and this is one of the most successful surgeries done.
Not necessarily. If you have exhausted nonoperative treatments such as nsaid's, therapy, and possibly injections then surgery as the appropriate option to consider. The surgery can be performed both arthroscopically or thru an incision. Results are comparable. Following repair we rely on your body being able to heal the repaired tendon back to its bony attachment on the ball of the shoulder. Retears can occur.
Generally low risk. Rotator cuff repair is commonly performed & usually low risk-medical risks depend on your health (heart, lung, etc health). The commonest complication/risk is in larger, more retracted, more chronic tears that have less predictable success rates for repair; if you have any doubts get a 2nd opinion; if your ortho and primary mds recommend surgery the risks are reasonable. If you smoke, quit.
Riske like how? All surgery has basic risks in general so there is a risk in any surgery. Specific 2 the shoulder the common risks would b failure of the repair, infection, a secondary adhesive capsulitis. As far as a dangerous surgery, no.
No. Rotator cuff repair surgery can be done very safely these days and with minimal risk. Although some tears can be challenging to repair, risks from the surgery itself are minor and unusual. An experienced surgeon with high skill with arthroscopic and open techniques can usually achieve excellent clinical results.