Who are you trying to marry? Did you do the quest for that NPC so that they will like you enough to want to marry you? My understanding is that if an NPC says "it's a fine day with you around" then the marriage options will pop up when you wear the amulet. If you did the quest but don't get the I like you dialogue, maybe something went wrong. Maybe you can use a console command to reset the NPC's attitude so that they like you, if there was some sort of bug with their quest, or if you did something else to piss them off. I know that buying of amulet of mara in riften. Thats pretty basic. What I am trying to say is that for example jordis the sword maiden, she would say "is that an Amulet of mara im surprised i yadda yadda" BUT the marriage option is not found. theres no "are you interested in se.." (Just kidding on se)