trademark question / case study

[nicorlino]

I have a question to you all,

say I own opium.com. A potential enduser is opiummiami.com. However it looks like they probably filed that trademark:
tm
and maybe some others. Could I offer them opium.com for sale without loosing it as long as I do not advertise anything related to them on the opium.com website?

Best Regards
Nico