Torn letter is a paper note in Fallout 4.
You know how much I miss you. But it's too dangerous. If you stay in Diamond City, at least I know you're safe.
If your mind's really made up, then be careful. Travel at night. Stick to the river. And whatever you do, don't go into the Common.
Gunners are moving into Back Bay. Word is they're after something in the old HalluciGen building. Keep your distance until they clear out.