Start slow. Pick a friend you want to get to know better, share some light shared domain related concern or fear with them (work related, hobby related, etc),

Start slow. Pick a friend you want to get to know better, share some light shared domain related concern or fear with them (work related, hobby related, etc), and see how it is received. If they are empathetic and supportive then you can open up more over time as you build trust. If they aren't serious or brush you off then you haven't really lost much social capital and you can move on to someone else.