The simplest way to say "I love you" in Korean is "saranjé", but there are also other expressions you can use to express your affection. Here are some phrases that may be useful to you.
Steps
Method 1 of 3: Direct Ways to Say "I Love You"

Step 1. Say "saranjé" or "saranjeyó"
Use this phrase to tell someone "I love you" in Korean.
- Pronounce the phrase like this: "sa-ran-je-yó".
- In Hangul, "saranjé" is written: 사랑해, and "saranjeyó" is written: 사랑 해요
- "Saranjé" is the most casual way of saying "I love you" and "saranjeyó" is the formal way of expressing the same feeling.

Step 2. Say "ni-ga yo-a"
Use this phrase to tell someone "I like you" in a romantic way.
- Pronounce the phrase like this: "ni-ga yo-a".
- In Hangul, this expression is written like this: 네가 좋아
- The phrase literally translates to "I like you." This particular expression can only be used on casual occasions only in a romantic context.

Step 3. Be formal with "dan-shin-i yo-a-yo"
This phrase could also be used to say to someone "I like you" in a romantic way.
- Pronounce the phrase like this: "dang-shin-i yo-a-yo".
- In Hangul, this expression is written like this: 당신 이 좋아요
- This phrase is also translated as "I like you", but in particular it is used to indicate a high level of respect or formality. Also, it should only be used in a romantic context.
Method 2 of 3: Other phrases to express love

Step 1. Declare "dang-shin-apshi motsal-a-yo"
This is the formal way of expressing how much you need that person in your life.
- Pronounce the expression like this: "dang-shin-aps-shi mot-sal-a-yo".
- Roughly, that phrase means: I can't live without you.
- In Hangul, this expression is written like this: 당신 없이 못 살아요
- A more informal way of saying it would be: "na-apsshi motsará" or 너 없이 못 살아

Step 2. Tell someone special "na-bak-e apss-a"
Use this phrase to tell someone that they are unique.
- Pronounce the expression like this: "na-bak-e aps-a".
- A rough translation would be: there is no one like you.
- In Hangul, this expression is written like this: 너 밖에 없어
- A more formal way of expressing the same sentiment would be: "dang-shin-bak-e apss-a-yo" or 당신 밖에 없어요

Step 3. Say firmly:
"gatchi itgo shipa". This phrase lets the other person know that you want to have a romantic relationship with them.
- Pronounce the phrase like this: "gat-chi it-gó shi-pa".
- If translated literally, this phrase means: I want to be with you.
- In Hangul, this expression is written like this: 같이 있고 싶어
- To make this expression more formal, say: "gatchi itgo shipaji" or 같이 있고 싶어요

Step 4. Ask someone out by asking:
"Na-rang sa-güil-lé?" This is the standard question to ask someone to date.
- Pronounce the question like this: "na-rang sa-güil-lé".
- Roughly translated it means: would you like to go out with me?
- In Hangul, this question is written like this: 나랑 사귈래?
- If you want to ask this question in a more formal way, say: "ya-rang sa-güil-le-yó?" or 저랑 사귈 래요?

Step 5. Propose to someone with "na-rang guiul-jon-jé- yu-lé?
"If things start to get serious and you want to ask your partner for his hand, that is the question you will need.
- Pronounce the question like this: "na-rang gui-yul-jon-je-yu-lé".
- This phrase means: will you marry me?
- In Hangul, this question is written like this: 나랑 결혼 해 줄래?
- A more formal way to ask the question would be: "ya-rang guiul-jon-jé-yu-lé-yo?" or 저랑 결혼 해 줄래요?
Method 3 of 3: Related Phrases

Step 1. Tell someone "bo-go-shi-peu-yo"
Use this phrase to tell someone that you miss them.
- Pronounce the expression like this: "bo-go-shi-pi-o-yo".
- A more direct way to translate the phrase would be: I want to see you.
- In Hangul, this expression is written like this: 보고 싶어요
- A more casual way of expressing the same sentiment would be to remove the "I" or 요 at the end of the sentence.

Step 2. Tell a girl "á-ruum-dab-da"
This is a great way to compliment a girl you like.
- Pronounce the expression like this: "á-rum-dab-dá".
- This phrase means: you are beautiful.
- In Hangul, this expression is written like this: 아름다워

Step 3. Tell a girl, "niun-yal séng-yinguioya."
This is a great way to compliment a guy you like.
- Pronounce the expression like this: "ni-un-yal séng-yin-gui-o-ya".
- This phrase means: you are handsome.
- In Hangul, this expression is written like this: 는 잘 생긴거

Step 4. Playfully say "chu-wo
An-a-yuo"Use this expression when you want to hug your loved one.
- Pronounce this expression like this: "chu-wo an-a-yuo".
-
Literally, this phrase means: I am cold. Hug me!
- "Chu-wo" means: I am cold.
- "An-a-juo!" means: hug me!
- In Hangul, this expression is written like this: 추워. 안아줘!

Step 5. Keep someone by your side by saying "narang gatchi issa"
This phrase should be used when you don't want someone to go home at the end of a romantic evening.
- Literally, this phrase means: stay with me.
- In Hangul, this expression is written like this: 나랑 같이 있어