My family boarded your company's plane on our trip for celebrating my grandpa and grandma's golden wedding anniversary. We had a surprise present from flight attendants at that time. This was too touching event to forget, so I decided to become a flight attendant who can provide passengers with memorable service. I had a chance to talk with flight attendants while I was going on job hunting, and I found their attractive personality and the desire to improve themselves. As the result, I strongly desire to join your company and give satisfaction to customers through my service now.
最後の文章は「御社に入れてください！」とアピールする部分なので、「思うようになりました」というモヤっとした表現をstrongly desire to という強い表現に変えました。