"We'll get it sorted" means we will handle the problem to find the resolution of it. Basicly, it is just a promise to deal with something, but whether we achieve any positive results still a question.

The word "sorting" has following different meanings: 1) to find a solution 2) to organise 3) to punish someone So when you say "We'll get it sorted" it's meaning depends on the situation . If for example you have a complicated situation/problem and you say "We'll get it sorted" , you will mean " lets solve this problem (either solve it yourselves or by asking someone to help ) ".....but basically your intention is to solve the problem.