Hello rausku. Reading your situation I guess this man is not ready or maybe available for dating right now. There are many reasons for why a person may decline a going out invitation-maybe he is going out/dating someone else, or maybe he is married or simply not interested. I would not try to persuade him anymore on this matter-if I were you of course. Doing it so may make you seem desperate or as a stalker, I am sure you don't want this specially within your professional/work environment. Additional to this, remember that even if he'll not be working together with
you doesn't mean you two are not working colleagues since you'll still be part of the same facility. I mentioned the work part since it is important to review workplace policies on dating, but that's an entirely different and more complex subject.
It is hard to "move on" specially on a situation like yours when there is attraction and flirting going on and after dropping an invitation with hopes of moving further but don't be fooled by this since unfortunately some people are "flirts" just for fun. In my work there is a guy that behaves that way; he flirts a lot and is already in a compromised relationship
. Unless there is mutual interest on spending more time with you after work, from my perspective he was just being very polite. I think it would be more productive to focus your attention on things you enjoy doing and get the best from that. That could help on not concentrating so much on the frustrating circumstances you're facing right now (we all have been through that)
. Who knows if maybe there is someone else who would be willing on spending time with you and be worth of your time and affection but goes unnoticed since you're not ready to give up on this another guy who's not available for you on this moment. Nobody should feel "forced" on saying yes to an invitation, you deserve to be surrounded by people and a date who would enjoy having you as a company.
My best wishes for you.