Regional economies are sufficiently robust to withstand the effects of contagion. The economies of Japan and South Korea, for example, are strong and active investors in the region. This is especially true if the trade war is not long-lived; the scale of the effects depends on the length of the war.
Furthermore, the claim of long-term loss of investor confidence assumes that China will fare poorly in the trade war, thus triggering contagion. This claim is evaluated elsewhere in this issue; should it be false, then investor confidence will be restored as China weathers the storm successfully.