To want, wish for, or desire something.
When to use
expressing desire, positive need, hopeful situation
The nuance
Use 원하다 to express positive desire or need for something, such as a person, object, or state. It never implies rejection or refusal.
원하다 (won-ha-da, wonhada) · 거부하다 (geo-bu-ha-da, geobuhada)
원하다 (wonhada) expresses positive desire for something, while 거부하다 (geobuhada) expresses negative rejection or refusal; both show attitudes toward an object but in opposite ways.

One lane per word — no nested boxes, just the gist.
To want, wish for, or desire something.
When to use
expressing desire, positive need, hopeful situation
The nuance
Use 원하다 to express positive desire or need for something, such as a person, object, or state. It never implies rejection or refusal.
To refuse or reject a proposal, request, or offer.
When to use
refusal situation, negative attitude, rejecting requests
The nuance
Use 거부하다 to clearly express refusal or rejection of something like a request or proposal. It conveys a negative attitude and is the opposite of 원하다. It cannot express positive desire.
나는 새 차를 원한다.
na-neun sae cha-reul won-han-da., na neun sae cha reul won han da.
Expresses positive desire, so 원하다 is correct.
나는 그 제안을 원한다.
na-neun geu je-an-eul won-han-da., na neun geu je an eul won han da.
Used for positively wanting a proposal.
나는 그 제안을 거부한다.
na-neun geu je-an-eul geo-bu-han-da., na neun geu je an eul geo bu han da.
Appropriate to refuse a proposal.
나는 새 차를 거부한다.
na-neun sae cha-reul geo-bu-han-da., na neun sae cha reul geo bu han da.
Refusing an object like a car is unnatural; 원하다 should be used.
그는 내 도움을 원하지 않는다.
geu-neun nae do-um-eul won-ha-ji an-neun-da., geu neun nae do um eul won ha ji an neun da.
Negative form of 원하다 expresses lack of desire.
그는 내 도움을 거부한다.
geu-neun nae do-um-eul geo-bu-han-da., geu neun nae do um eul geo bu han da.
Used to express refusal of help.
나는 그의 의견을 원하지 않는다.
na-neun geu-ui ui-gyeon-eul won-ha-ji an-neun-da., na neun geu ui ui gyeon eul won ha ji an neun da.
Expresses lack of desire for opinion.
나는 그의 의견을 거부한다.
na-neun geu-ui ui-gyeon-eul geo-bu-han-da., na neun geu ui ui gyeon eul geo bu han da.
Used to reject an opinion.
Which sentence expresses 'refusal'?
When should you use '원하다'?
Which sentence requires '거부하다'?