What algorithms are available to identify similarity scores between two records? I have data that looks like this:

priority    task         area 
1           clean room   living room
2           clean room   living room
2           water plants bedroom


I want to identify records with a priority of 2 that should be a priority of 1 based on similarity between the priority 2 task and each priority 1 task. 

The result data would look like this:

priority    task         area         propensity_for_priority_1
1           clean room   living room  1
2           clean room   bedroom      .5
2           water plants bedroom      0


String similarity does not need to be performed (i.e. living room and bedroom are mutually exclusive). Is there a matching algorithm that can be used to compare various fields and result in one propensity_for_priority_1 score for each record?
2 Approaches.

a) Siamese networks, let the net tell you whats similiar and what lies together.

b) just perform multiclassification if the data permits, I dont know all the details but it looks like it.