First time in Colombia

Going to meet my wife, who is visiting family in Cali. I am not really going for a vacation as such, more so to visit her family as we have never met.

A couple of questions, what is the best way to pay for things? My bank debit card says it has a lot of foreign transaction fees. Should I exchange for pesos when I arrive?

Also, I have talked to a lot of Colombian people and American people, and they told me that Cali is very dangerous, with kidnappings and crime. My wife has a house in Cali and we will be staying there. I understand about not acting American and dressing conservatively. I'm older and pretty quiet.

Any thoughts on the likelihood of criminal events?