Unfortunately, politics is a little more complicated than this. We don't know what the best answer to Putin's aggression is. Giving him Crimea without any protest and ending the sanctions might make him more hungry. Finland (along with the Baltic states) could be high on his list for future aggression. Finland has an advantage over the Baltic states, though, because Finland isn't in NATO.
Besides, what gives you a non-warmonger vibe from Trump? Have you heard him talking about ISIS or Iran? He seems ready for a full-on war with Iran over the next provocation, which happen frequently, because parts of Iran's military are unhappy with the nuclear deal. This rhetoric may be bluffing to keep Iran in line and lessen the provocations, but then, taking a hard stance on Putin's aggression follows that same philosophy.