watashi wa kono chansu o taisetsu ni shimasu.

I will value this opportunity.

Breakdown of watashi wa kono chansu o taisetsu ni shimasu.

• は: topic particle
• 私わたし: I
• を: direct object particle
• この: this

Questions & Answers about watashi wa kono chansu o taisetsu ni shimasu.

What is the role of は in 私は here, and how is it different from が?

は is the topic marker. In 私はこのチャンスを大切にします, it sets 私 (I) as the topic: “As for me, …”.

• 私は = “As for me, … / I, (speaking about myself), …”
• The rest of the sentence is information about that topic.

If you used が instead (私がこのチャンスを大切にします), it would emphasize I as the one who will value this chance, often in contrast to someone else:

• 私がこのチャンスを大切にします。
  “I will (be the one to) value this chance.” (implying maybe others won’t, or in response to “Who will do it?”)

So:

• は: sets a general topic, often neutral: “I will value this chance.”
• が: marks the subject with a sense of focus or contrast: “I will be the one who values this chance.”

Why are there two particles, を and に, and what do they each do in this sentence?

In このチャンスを大切にします:

• を marks the direct object:
  このチャンスを = “this chance” as the thing the action is done to.

• に is part of the pattern X に する, here combined with 大切:

  • 大切にする literally: “to do/make (something) in an important/precious way”
  • Functionally: “to value / to cherish / to treat as important”

So the structure is:

• このチャンスを (object)
• 大切に (in an “important” manner)
• します (do)

Altogether: “(I) will treat this chance as something important / I will value this chance.”