For this achievement you must complete the game with only heart decisions. Start a new game and make sure that you choose the one that has a heart symbol in each decision.
It is sometimes difficult to see.
Sometimes there are situations where you have two head options. If you have this situation you must say nothing. If you just let the time run out, you can start over the game. Whenever you have the opportunity, you must select the heart symbol.
If you don't say anything even though you have a heart symbol, the achievement is also gone and you can start again. As soon as the advertising for Little Hope starts, the achievement should come.