Breaking a Promise When Choosing One of the Job Offers

I am kindly writing to get a clarification about breaking a promise. I applying for different jobs and there is a situation in that I sent my application to several jobs, the ones I like more and the ones I like, yet not as much as the others. So I have gone through a long qualification process for a job that I like, yet not so much and now I am being accepted for it. The only thing now is to sign a job agreement and I promised the employer that I will work on this job. And suddenly, there is a reply from a job that I would like to work the most and more than on other jobs, that they would like to talk to me after I finished their qualification, which, in turn, illustrates my intention to work on their job and makes a promise to work there. So now I am in a situation where I have two job offers, for the one I like more and the one I like less. I would like to work in a job I like more, however, I already made a promise to work for a job that I like less. What should I do in this scenario? And will making a decision in favor of one or another job break one of my promises? Is making a decision to reject signing the agreement of the job I like more in favor of the job I just got a response from considered breaking a promise? And is it a sin?

I would really appreciate your clarification and thank you in advance.