In Avengers: Infinity War, Thanos pays a pretty high price to obtain the Soul Stone. However, it's been shown that he's okay with sending minions to collect Infinity Stones, who later hand them over to him "willingly". It seems that the logical thing to do would be to turn back on Vormir and send a minion to make that sacrifice.

Why would Thanos be willing to make such a important sacrifice?

Two thoughts come to mind - one, that there's a kind of security-check built into the Soul Stone that makes it impossible to hand over the stone. Two, that Thanos trusts no-one else to make this sacrifice and believes that he alone has the willpower to earn the Soul Stone. Both of these feel fairly weak to me, especially the second one - there are always things that people will want more than love, particularly if one's being manipulated by a Mad Titan.

In Avengers: Infinity War, Thanos pays a pretty high price to obtain the Soul Stone. However, it's been shown that he's okay with sending minions to collect Infinity Stones, who later hand them over to him "willingly". It seems that the logical thing to do would be to turn back on Vormir and send a minion to make that sacrifice.

Why would Thanos be willing to make such an important sacrifice?

Two thoughts come to mind - one, that there's a kind of security-check built into the Soul Stone that makes it impossible to hand over the stone. Two, that Thanos trusts no-one else to make this sacrifice and believes that he alone has the willpower to earn the Soul Stone. Both of these feel fairly weak to me, especially the second one - there are always things that people will want more than love, particularly if one's being manipulated by a Mad Titan.