たがるTo want to (Third person)

The たい form expresses personal desires, such as 日本に行きたい ('I want to go to Japan'). がる, on the other hand, is a suffix that shows when someone else appears to want something, like 日本に行きたがっている ('They seem like they want to go to Japan'). The たい form is typically not used for expressing others' desires unless quoting the subject.

がる attaches to adjectives to describe the observed feelings or desires of another person, e.g. 寒がる 'seems cold', ほしがる 'seems to want (A)', and so on. When combined with the たい-form of verbs, it becomes たがる, expressing observed desire, e.g. 飲みたがる 'seems to want to drink'.

がほしい and たがる both express desire but differ in usage. がほしい is used for the speaker's own wants, e.g. 車がほしい ('I want a car.'). たがる combines the たい-form of verbs with がる to describe a third person's apparent desire to do something, e.g. 田中さんは車を買いたがっている ('Tanaka seems to want to buy a car.').

てほしい and たがる both express desire but in different ways. てほしい is used when the speaker wants someone else to do something, e.g. これを買ってほしい ('I want you to buy this.'). たがる combines the たい-form with がる to describe a third person's apparent desire, e.g. 田中さんは車を買いたがっている ('Tanaka seems to want to buy a car.').