It sure is.

From Space Tree Wiki

Throughout Space Tree, sentences like "It sure is," "We sure do," and "They sure have" have popped up frequently in the dialogue. Most of them are said in a reassuring manner, with emphasis on the word "sure" (as demonstrated in Ed Atlin's "Where's My Shoe" animation's easter egg). Here are a few examples:

• Space Girlfriend:
  • CHRISTOPHER 1: Yes. Your fiancee is quite talented.
    

CHRISTOPHER 2: She sure is.

• Desert Space:
  • MIRAGE: I'm gonna plant you in the ground until you grow into a super Space Tree!
    

SPACE TREE: What? That's retarded!

MIRAGE: It sure is!

• Super Space:
  • COMMANDER: ...but do we have a getaway vehicle or what?
    

PINKFROSTING88: You sure do!

• Emotional Distress:
  • SPACE TREE: And your time is up. Did you finish it?
    

COMMANDER: I sure did, Space Trizzle.

• Slave Grave:
  • FREELY MCWHEELY: You won't be telling anyone what you saw here.
    

ALLON: I sure won't.

• Career Fear:
  • YOUNG COMMANDER: Hell yeah, we could! Because we're gifted.
    

SPACE TREE: We sure are.

• No Chalk:
  • SPACE TREE: Oh, Commander. You're such a wacky and zany guy.
    

COMMANDER: I sure am, Space Tree!

• Panic Broom:
  • SPESHDIV ROBOT: As you can plainly see, this shizznip is the shizznit.
    

COMMANDER: It sure is, my good man.

• Serious Tingling:
  • COMMANDER: Hey Space Tree, you wanna go help the less fortunate?
    

SPACE TREE: I sure do!

• The Giving Tree:
  • Page title: We sure do
  • WARDEN: Thank you, friend. That's very generous of you.
    

SPACE TREE: It sure is.

• • SPACE TREE: At least I'm more charitable than Allon.
    

COMMANDER: Well, that's true.

ALLON: It sure is.