How do you guys ever so know that you're ready for a commitment/marriage?

I want a long living happy commitment and healthy one. My friend is 30 and got married last month. I'm happy for her but I wish I had a long healthy happy relationship. She has been with her man for 6 years. My relationships never last because every guy says I'm too easy, never disagree and I sugarcoat to protect their feelings. My sister has a boyfriend and she is straightfoward and blunt but thoughtful.