[Casiopea]

Ah, but insane doesn't fit the mo(u)ld.

<c> is pronounced [ts]; <s> is pronounced [tsh]
(origin, Old & Middle French)
finance, finan[ts]e
chance, chan[ts]e
sense, sen[ts] *Old French sens
pension, pen[tsh]ion
tension, ten[tsh]ion

in+sane < Latin in- prefix "not"
in+ception < Latin in- prefix "in, on"
in+stant < Old French in- prefix "in"