Trending @Infosys; Onsite Opportunity During Notice Period

I am currently on my notice period. I had applied for a project demand opportunity and was mapped to it, but I informed them that I am on notice period and requested them to reject it as I was not sure about my eligibility. Now they contacted me again asking if I am interested in an onsite opportunity in Belgium. I told them I can consider it if they match my current offer. They said the process may take 8–10 months. I agreed but requested that I should receive a revised offer letter before my last working day. What should I do in this situation?