Cover letters are not for behind kissing as you say. They introduce you as a person to the employer. If this is a joke post so be it, but you need to take writing a cover letter seriously - are you actively searching for work now?
A professional resume or CV won't get you a job. It doesn't tell the employer anything about you. For example, what background do you have with your experience? Did you enjoy what you did, have you taken it further with extra study? What hours/days are you looking for? What hours/days etc can you NOT work? What can you bring personally to the job they are advertising?
What are your interests? Do you like working with certain patient groups, and why are you applying for that particular job?
A cover letter gives you the opportunity to talk a bit about yourself and plug yourself. And you don't have to kiss anyone's behind - experienced employers would know if you were flattering them unnecessarily. They want a letter that states the real you, and to give them an idea of what you think, some info on what you are like as a person, and a chance to see your grammar
and English skills.
My experience from working in clinical nursing HR for 3 years.