A person who finds it difficult to refuse others is a very USEFUL person. You can dump a lot of work on them. They will never refuse anything for their loved ones. They will always help out, assist and lend you money.
What should you do?
It's worth starting off with your first, very small "NO"!
Continue to assert yourself in this skill;
• Give yourself the right to act how you plaese. Act in your own interests.
• Practice saying "no" to strangers – consultants in stores, waiters, neighbors.
• Choose an acceptable form of refusal for yourself. Sharp, soft, playful or serious – there are many options.
• The fear of rejection is the fear that you will be judged. You very well might be, so what? It's just someone's opinion...
Of course, there will be people who will not accept you and your "no", even your loved ones will not like it. But those to whom you are important, who want to be close, respect you, will stay close.